Water-washed fine and coarse recycled aggregates for real scale concretes production in Barcelona

Citation: Etxeberria, M.; Konoiko, M.; Garcia, C.; Perez, M.Á. Water-Washed Fine and Coarse Recycled Aggregates for Real Scale Concretes Production in Barcelona. Sustainability 2022,14, 708. https://doi.org/10.3390/ su14020708 Academic Editor: Jianzhuang Xiao Received: 15 December 2021 Accepted: 7 January 2022 Published: 9 January 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Article Water-Washed Fine and Coarse Recycled Aggregates for Real Scale Concretes Production in Barcelona Miren Etxeberria 1,* , Mikhail Konoiko 1, Carles Garcia 1and Miguel Ángel Perez 2 1Department of Civil and Environmental Engineering, Campus Nord, Universitat Politècnica de Catalunya·BarcelonaTECH, 08034 Barcelona, Spain; [email protected]u (M.K.); garciaur[email protected] (C.G.) 2Hercal Diggers S.L., Ctra de Rubí, 286-B, 08228 Terrassa, Spain; [email protected] *Correspondence: mir[email protected]; Tel.: +34-934011788 Abstract: The use of recycled aggregate to reduce the over-exploitation of raw aggregates is necessary. This study analysed and categorised the properties of water-washed, fine and coarse, recycled aggregates following European Normalization (EN) specification. Because of their adequate properties, zero impurities and chemical soluble salts, plain recycled concrete was produced using 100% recycled concrete aggregates. Two experimental phases were conducted. Firstly, a laboratory phase, and secondly, an on-site work consisting of a real-scale pavement-base layer. The workability of the produced concretes was validated using two types of admixtures. In addition, the compressive and flexural strength, physical properties, drying shrinkage and depth of penetration of water under pressure validated the concrete design. The authors concluded that the worksite-produced concrete properties were similar to those obtained in the laboratory. Consequently, the laboratory results could be validated for large-scale production. An extended slump value was achieved using 2.5–3% of a multifunctional admixture plus 1–1.2% of superplasticiser in concrete production. In addition, all the produced concretes obtained the required a strength of 20 MPa. Although the pavement-base was produced using 300 kg of cement, the concrete made with 270 kg of cement per m 3 and water/cement ratio of 0.53 achieved the best properties with the lowest environmental impact. Keywords: recycled concrete aggregate; recycled aggregate concrete; workability; compressive strength; pavement 1. Introduction In 2018, construction and demolition waste was 35.4% of the total waste (2277 million tonnes) generated in the European Union (EU) by all economic activities including households, of which only 54.2% was recovered [ 1 , 2 ]. Consequently, the demolition of concrete structures causes a considerable volume of waste that terminates in landfills. The guidelines of the European Commission [ 3 ] are designed to encourage a change in production procedures to embrace a circular, more sustainable and eco-respectful model in which waste is re-introduced into production processes, reducing raw material over-exploitation and maximising material life cycles. Plaza et al. [ 4 ] concluded that the benefits of using recycled coarse and fine aggregates to replace natural aggregate partially lie not only in CO 2 emissions reduction in concrete manufacture but also in the significant mitigation of the environmental impacts induced by stockpiling the respective waste. Moreover, about 75–80% of the total concrete components materials are aggregates [ 5 ]. Today, the production and use of natural resources such as natural aggregates in concrete production reduce natural resources and increase the volume of atmospheric pollutants [ 6 ]. Therefore, recycling waste concrete and concretes from damaged or demolished structures are essential for producing recycled concrete aggregates (RCA), thus mitigating the environmental impacts. The demand for non-renewable natural resources and industrial products, especially mineral aggregates from quarry extraction, is high for highway construction and main19 Sustainability 2022,14, 708 tenance [ 7 ]. Therefore, the most widespread practice to achieve pavement sustainability is to lower the quantity of virgin aggregates by partially or fully replacing them with alternative aggregates. In addition, the available literature shows that alternative aggregate, as recycled concrete aggregate, could be effectively used for concrete pavements [ 8 – 11 ]. The mentioned field investigation results indicate that it is possible to produce pavements from recycled aggregates that are equivalent in all aspects to pavements made with conventional aggregates when up to 40% of coarse RCA are used to replace natural aggregates. Gress et al. [ 12 ] described that the pavement produced with up to 25% of fine recycled concrete aggregates also achieved adequate properties although with a slight increase of shrinkage value with respect to that in concrete produced only employing coarse RCA. Moreover, recycled concrete made with coarse RCA aggregates have been employed in certain, although few, real structural concrete projects [ 13 ]. In Hong Kong [ 14 ], from 2022 to 2005, the acceptable behaviour of structural concretes grades C20 and C25 were verified, producing concretes with recycled coarse aggregate replacement levels of 100 and 20%, respectively. Zhang and Zhao [ 15 ] also proved 50% coarse RCA in structural concrete production. However, for the structural elements studied by Xiao et al. [ 16 ], up to 30% of coarse RCA were used in concrete production. The use of RCA is still limited. However, as mentioned previously, coarse recycled aggregates (C-RCA) have been proven to be suitable for concrete production [ 17 ]. Moreover, their use in concrete production as a structural material has been widely analysed and validated in many applications [ 13 , 18 , 19 ]. However, the use of fine recycled concrete aggregates (F-RCA) is less widespread due to their more negative effect on concrete properties [20]. RCA aggregates have a lower quality than the natural aggregate (NA) because of attached mortar to the stone particles in RCA. In contrast to NA, RCA has the following properties: more water absorption, less bulk density, more abrasion loss and more crushability [ 21 , 22 ]. In particular, fine RCA could also have more dust particles, more organic impurities and also harmful chemicals because of earth mixing with concrete after building demolition [ 23 ]. Despite these weaknesses, the un-hydrated cement of the original concrete available in the RCA may play a positive role in its use in structural concrete. In addition, in the case of the use RCA, the specific surface of the aggregates improves the binder/recycled aggregate interface [24]. Coarse and fine RCA in concrete production affects workability and hardened-state (mechanical, physical and durability) properties. Recycled aggregate concrete (RAC) is typically associated with lower workability than natural aggregate concrete (NAC) of the same composition [ 25 ]. This is attributed to the poor shaping properties of crushed RCA when compared to NA. If there is proper compensation for water absorption, workability is essentially affected by the shape of the aggregates [ 26 , 27 ]. The reduction of workability is confirmed with the increased replacement of NA with RCA, especially in the finer fraction [ 28 ]. Partial absorption of the superplasticiser by the aggregates also occurs, and increased fines in the content are due to a partial loss of the aggregates’ mortar during the mixing process [ 26 ]. Tobori et al. [ 29 ] found that when superplasticiser is added to RAC mix, instead of acting on the cement grains, the absorption of its liquid phase occurs through F-RCA. Evangelista and de Brito [ 30 ] found that polymer chains have a larger contact area with fine recycled aggregates than natural ones. Nedeljkovi’c et al. [ 27 ], after an exhausted review analysis, concluded that researchers had offered many reasonable explanations on complex flow behaviour of recycled concretes through a combination of experiments and theories. They described that there is no universal approach to obtain and maintain satisfactory workability of mortars/concretes with F-RCA. It is generally believed that concrete compressive strength decreases as the amount of recycled concrete replacement increases [ 31 ], which may be due to the old mortar in fine RCA that makes concrete more porous and less dense [ 32 ]. As a result, the concrete produced with 100% RCA (coarse plus fine recycled aggregated) obtained a lower compressive strength [ 4 , 27 ]. However, the tensile strength can improve due to the improvement of the interface transition zone in concretes containing RCA [4,10]. 20 Sustainability 2022,14, 708 According to Zhang et al. [ 33 ], both F-RCA and C-RCA significantly influence the drying shrinkage behaviour of concrete. Total (100%) replacement of natural aggregates with RCA (including both F-RCA and C-RCA) increased the drying shrinkage by more than 100% (102.0–116.9%). In addition, a higher water absorption ratio and a lower density RCA resulted in higher shrinkage strains. However, compared with the influence of C-RCA, the effect of F-RCA is relatively lower. In particular, C-RCA with a 100% replacement ratio increased the drying shrinkage. Sadati and Khayat [ 9 ] also determined that the increasing the fine RCA content from 0 to 15% had no significant effects on drying shrinkage of pavement concrete. Although recycled concrete produced with 100% of recycled aggregate achieves a lower strength and a higher shrinkage than those of conventional concretes, the washing of recycled aggregates could guarantee the quality and consequently the durability of the concrete produced. In order to assure RCA aggregate quality, it is imperative to use innovative recovery plants to manage construction and demolition waste efficiently [34]. The recycled aggregates used in this study were obtained from an innovative recycling plant (see Figure 1) located in Barcelona, Spain. Two types of demolition material are treated separately at the plant: concrete waste (more than 95% is concrete) and mixed waste (with approximately 30% ceramic material). After crushing these to the desired aggregate size (usually 0/20 mm), the cleaning and sieving processes of the mixed recycled aggregates (RMA) and RCA are carried out. Fine (F-) and course (C-) fractions are produced separately, making them suitable for concrete production. In this study, the F-RCA and C-RCA were analysed for use in concrete production. Sustainability 2022, 14, x FOR PEER REVIEW 3 of 22 produced with 100% RCA (coarse plus fine recycled aggregated) obtained a lower compressive strength [4,27]. However, the tensile strength can improve due to the improvement of the interface transition zone in concretes containing RCA [4,10]. According to Zhang et al. [33], both F-RCA and C-RCA significantly influence the drying shrinkage behaviour of concrete. Total (100%) replacement of natural aggregates with RCA (including both F-RCA and C-RCA) increased the drying shrinkage by more than 100% (102.0%–116.9%). In addition, a higher water absorption ratio and a lower density RCA resulted in higher shrinkage strains. However, compared with the influence of C-RCA, the effect of F-RCA is relatively lower. In particular, C-RCA with a 100% replacement ratio increased the drying shrinkage. Sadati and Khayat [9] also determined that the increasing the fine RCA content from 0 to 15% had no significant effects on drying shrinkage of pavement concrete. Although recycled concrete produced with 100% of recycled aggregate achieves a lower strength and a higher shrinkage than those of conventional concretes, the washing of recycled aggregates could guarantee the quality and consequently the durability of the concrete produced. In order to assure RCA aggregate quality, it is imperative to use innovative recovery plants to manage construction and demolition waste efficiently [34]. The recycled aggregates used in this study were obtained from an innovative recycling plant (see Figure 1) located in Barcelona, Spain. Two types of demolition material are treated separately at the plant: concrete waste (more than 95% is concrete) and mixed waste (with approximately 30% ceramic material). After crushing these to the desired aggregate size (usually 0/20 mm), the cleaning and sieving processes of the mixed recycled aggregates (RMA) and RCA are carried out. Fine (F-) and course (C-) fractions are produced separately, making them suitable for concrete production. In this study, the F-RCA and C-RCA were analysed for use in concrete production. Figure 1. CDW recovery plant to water-washed recycled aggregate [35]. The production of high-quality plain concrete using 100% water-washed fine and coarse RCA aggregates without employing natural aggregates can be possible if the recycled aggregates fulfil the requirements to be used in concrete production. The objective of this study was to analyse the quality of water-washed C-RCA and F-RCA aggregates produced in the innovative plant and validate them to be used in plain concrete production by building a real pavement-base layer. The production of plain concrete was analysed in two phases: (1) laboratory experiments and (2) on-site pavement-base layer construction. In the first phase, the suitable concrete mix proportions were tested to see if they accomplish the minimum required properties of having an adequate workability (6–8 cm of slump test) 30 min after RAC concrete production and a minimum compressive strength of 20 MPa at 28 days of curing. Moreover, other properties such as the flexural strength, physical properties, drying shrinkage and depth of penetration of water under pressure were also validated in the concrete design. The second phase would verify if the worksiteFigure 1. CDW recovery plant to water-washed recycled aggregate [35]. The production of high-quality plain concrete using 100% water-washed fine and coarse RCA aggregates without employing natural aggregates can be possible if the recycled aggregates fulfil the requirements to be used in concrete production. The objective of this study was to analyse the quality of water-washed C-RCA and F-RCA aggregates produced in the innovative plant and validate them to be used in plain concrete production by building a real pavement-base layer. The production of plain concrete was analysed in two phases: (1) laboratory experiments and (2) on-site pavement-base layer construction. In the first phase, the suitable concrete mix proportions were tested to see if they accomplish the minimum required properties of having an adequate workability (6–8 cm of slump test) 30 min after RAC concrete production and a minimum compressive strength of 20 MPa at 28 days of curing. Moreover, other properties such as the flexural strength, physical properties, drying shrinkage and depth of penetration of water under pressure were also validated in the concrete design. The second phase would verify if the worksite-produced concrete achieved adequate properties similar to those obtained in the laboratory. 21 Sustainability 2022,14, 708 2. Materials and Methods 2.1. Materials 2.1.1. Cement and Chemical Admixtures The cement CEM II A-L 42.5 R (88% clinker, 12% limestone, excluding the set regulator, added in 5%) was used. The composition of the cement is shown in Table 1. Table 1. Composition of cement as the percentage of total weight. Cement SiO2CaO Fe2O3Al2O3MgO SO3Na2O K2O LOI CEM II A-L 42.5 R 19.33 62.71 2.65 3.43 1.36 3.52 0.06 0.8 5.28 Two chemical admixtures were employed for concrete production: a multifunctional admixture (P) and a superplasticiser (S). The mix recommended by the manufacturer for the S was 0.3–2.0% and 0.5–1.5% for the P admixtures based on the weight of the cement. 2.1.2. Recycled Concrete Aggregate Production and Its Properties The production of C-RCA and F-RCA aggregates was conducted in an innovative washing recycling plant. Once all the polluted components, big pieces of steel, wood or plastic, are removed from the demolition waste, the clean concrete waste is crushed to 0/20 mm recycled aggregate fractions. At this point, the water-washed treatment process and different aggregate fraction production starts: (1) the 0/20 mm fractions are transported to the recovery plant by conveyor belt for the next steps in the process. The recycled material is passed through a magnetic separator, and under the water spraying process, the 0/20 mm fractions pass through a 4 mm sieve where the fine and coarse fractions are separated. (2) The recycled aggregate fractions finer than 4 mm go to the hydro-cyclone separators. At this point, the material is divided into three recycled fraction sizes: 0/4 mm, 0/2 mm and a fraction finer than 63 µ m (filler and clay). (3) After the cleaning process (with water and brushing), the coarse recycled aggregate fractions (>4 mm) are sieved in three different fractions, 14/20 mm, 8/14 mm and 4/10 mm. Although the cleaning procedure is conducted via a water system, the entire volume of water employed in the treatment process is reused satisfactorily. In addition, rainwater is also harvested through storage tanks. Four fractions (0/2 mm, 0/4 mm, 4/10 and 8/20) of RCA, designated FR1, FR2, CR1 and CR2, respectively, were used for concrete production (see Figure 2). The 8/20 mm fraction was produced mixing the fractions 8/14 mm 50% and 14/20 mm 50%. The recycled aggregates were characterised following EN 12620 “Aggregates for concrete” specifications. Sustainability 2022, 14, x FOR PEER REVIEW 4 of 22 produced concrete achieved adequate properties similar to those obtained in the laboratory. 2. Materials and Methods 2.1. Materials 2.1.1. Cement and Chemical Admixtures The cement CEM II A-L 42.5 R (88% clinker, 12% limestone, excluding the set regulator, added in 5%) was used. The composition of the cement is shown in Table 1. Table 1. Composition of cement as the percentage of total weight. Cement SiO2 CaO Fe2O3 Al2O3 MgO SO3 Na2O K2O LOI CEM II A-L 42.5 R 19.33 62.71 2.65 3.43 1.36 3.52 0.06 0.8 5.28 Two chemical admixtures were employed for concrete production: a multifunctional admixture (P) and a superplasticiser (S). The mix recommended by the manufacturer for the S was 0.3%–2.0% and 0.5%–1.5% for the P admixtures based on the weight of the cement. 2.1.2. Recycled Concrete Aggregate Production and Its Properties The production of C-RCA and F-RCA aggregates was conducted in an innovative washing recycling plant. Once all the polluted components, big pieces of steel, wood or plastic, are removed from the demolition waste, the clean concrete waste is crushed to 0/20 mm recycled aggregate fractions. At this point, the water-washed treatment process and different aggregate fraction production starts: (1) the 0/20 mm fractions are transported to the recovery plant by conveyor belt for the next steps in the process. The recycled material is passed through a magnetic separator, and under the water spraying process, the 0/20 mm fractions pass through a 4 mm sieve where the fine and coarse fractions are separated. (2) The recycled aggregate fractions finer than 4 mm go to the hydro-cyclone separators. At this point, the material is divided into three recycled fraction sizes: 0/4 mm, 0/2 mm and a fraction finer than 63 µm (filler and clay). (3) After the cleaning process (with water and brushing), the coarse recycled aggregate fractions (>4 mm) are sieved in three different fractions, 14/20 mm, 8/14 mm and 4/10 mm. Although the cleaning procedure is conducted via a water system, the entire volume of water employed in the treatment process is reused satisfactorily. In addition, rainwater is also harvested through storage tanks. Four fractions (0/2 mm, 0/4 mm, 4/10 and 8/20) of RCA, designated FR1, FR2, CR1 and CR2, respectively, were used for concrete production (see Figure 2). The 8/20 mm fraction was produced mixing the fractions 8/14 mm 50% and 14/20 mm 50%. The recycled aggregates were characterised following EN 12620 “Aggregates for concrete” specifications. (a) FR1: 0/2 mm (b) FR2: 0/4 mm (c) CR1: 4/10 mm (d) CR2: 8/20 mm Figure 2. The four recycled aggregates (each line in the ruler are 10 mm). The constituents of C-RCA aggregates (CR1 and CR2) were: Rc (Concrete and mortar) + Ru (unbound aggregate) of 96.27%, Rb (Ceramic) 1.94%, Ra (Asphalt) 1.40% and X (other impurities) 0.4%, determined following the EN 933-11:2009 specifications. According to 22 Sustainability 2022,14, 708 the EN 12,620 specifications, the RCA aggregates composed of more than 95% concrete are categorised as Type A (Rc90, Rcu95, Rb10, Ra1, FL2 and XRg1). The grading distribution of the four fractions of recycled aggregates 0/2 (FR1), 0/4 (FR2), 4/10 (CR1) and 8/20 (CR2) are shown in Figure 3. They were determined following EN 933-1 specification. According to the grading distribution, the fine fractions (FR1 and FR2) were categorised as Gf85. The 4/10 gravel fraction was classified as Gc90/15 and the 8/20 fraction as Gc85/20, the categories being highlighted by the Spanish concrete Structural Code [36]. Sustainability 2022, 14, x FOR PEER REVIEW 5 of 22 Figure 2. The four recycled aggregates (each line in the ruler are 10 mm). (a) FR1: 0/2 mm (b) FR2: 0/4 mm (c) CR1: 4/10 mm (d) CR2: 8/20 mm The constituents of C-RCA aggregates (CR1 and CR2) were: Rc (Concrete and mortar) + Ru (unbound aggregate) of 96.27%, Rb (Ceramic) 1.94%, Ra (Asphalt) 1.40% and X (other impurities) 0.4%, determined following the EN 933-11:2009 specifications. According to the EN 12,620 specifications, the RCA aggregates composed of more than 95% concrete are categorised as Type A (Rc90, Rcu95, Rb10, Ra1, FL2 and XRg1). The grading distribution of the four fractions of recycled aggregates 0/2 (FR1), 0/4 (FR2), 4/10 (CR1) and 8/20 (CR2) are shown in Figure 3. They were determined following EN 933-1 specification. According to the grading distribution, the fine fractions (FR1 and FR2) were categorised as Gf85. The 4/10 gravel fraction was classified as Gc90/15 and the 8/20 fraction as Gc85/20, the categories being highlighted by the Spanish concrete Structural Code [36]. Figure 3. The grading distribution of all the recycled concrete aggregate fractions (FR1, FR2, CR1 and CR2). The coarse recycled aggregates (CR1 and CR2) contained less than 1.5% of particles under 63 µm classified in the maximum category of f1.5. In addition, the FR1 and FR2 had a filler quantity of less than 3%. Therefore, they were assigned the top category f3. The density and absorption capacity of all the aggregates fractions, described in Table 2, were determined following UNE-EN 1097-6 specification. All recycled aggregates met the requirements of the Structural Code [36] at 7% (established by the concrete Structural Code). It should be clarified that FR1 0/2 sand was always mixed with FR2 0/4 sand (using 20% 0/2 and 80% 0/4). Therefore, the mixture fraction met the limit set by the structural code of 7% absorption capacity. Furthermore, as mentioned above, all the used recycled aggregates were found to be well within the absorption limitation established by international regulations for recycled aggregates to be used in non-structural concrete. For example, 10% in Hong Kong and 20% in The International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM, Paris, France) German and Norwegian specifications [37]. Table 2. Dry density and absorption capacity of RCA. FR1-0/2 Desv FR2-0/4 Desv CR1-4/10 Desv CR2-8/20 Desv Dry Density (kg/dm3) 2.12 0.06 2.29 0.05 2.24 0.03 2.30 0.01 Absorption (%) 7.8 0.04 5.6 0.46 6.1 0.05 5.6 0.25 The per cent of acid-soluble sulphate and water-soluble chlorides salts were determined according to the EN 1744-1 specification. The limit established by the Structural Code for aggregates used in the manufacture of concrete is 0.8% and 0.05% of acid-soluble 0 10 20 30 40 50 60 70 80 90 100 0.01 0.10 1.00 10.00 Percent Passing (%) Sieve Size (mm) CR2 (8/20) CR1 (4/10) FR2 (0/4) FR1(0/2) Figure 3. The grading distribution of all the recycled concrete aggregate fractions (FR1, FR2, CR1 and CR2). The coarse recycled aggregates (CR1 and CR2) contained less than 1.5% of particles under 63 µ m classified in the maximum category of f1.5. In addition, the FR1 and FR2 had a filler quantity of less than 3%. Therefore, they were assigned the top category f3. The density and absorption capacity of all the aggregates fractions, described in Table 2, were determined following UNE-EN 1097-6 specification. All recycled aggregates met the requirements of the Structural Code [ 36 ] at 7% (established by the concrete Structural Code). It should be clarified that FR1 0/2 sand was always mixed with FR2 0/4 sand (using 20% 0/2 and 80% 0/4). Therefore, the mixture fraction met the limit set by the structural code of 7% absorption capacity. Furthermore, as mentioned above, all the used recycled aggregates were found to be well within the absorption limitation established by international regulations for recycled aggregates to be used in non-structural concrete. For example, 10% in Hong Kong and 20% in The International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM, Paris, France) German and Norwegian specifications [37]. Table 2. Dry density and absorption capacity of RCA. FR1-0/2 Desv FR2-0/4 Desv CR1-4/10 Desv CR2-8/20 Desv Dry Density (kg/dm3)2.12 0.06 2.29 0.05 2.24 0.03 2.30 0.01 Absorption (%) 7.8 0.04 5.6 0.46 6.1 0.05 5.6 0.25 The per cent of acid-soluble sulphate and water-soluble chlorides salts were determined according to the EN 1744-1 specification. The limit established by the Structural Code for aggregates used in the manufacture of concrete is 0.8% and 0.05% of acid-soluble sulphates and soluble chlorides, respectively. Table 3 summarises the obtained values. All recycled aggregates met the standard requirement. 23 Sustainability 2022,14, 708 Table 3. Chemical analysis of recycled aggregates. FR1-0/2 FR2-0/4 CR1-4/10 CR2-8/20 Acid soluble Sulphate (%) 0.13 0.11 0.23 0.16 Water-Soluble Chloride salts (%) 0.005 0.0014 0.007 0 The shape factor and Los Angeles abrasion coefficient of coarse recycled aggregate fractions were determined following UNE-EN 933-3 and UNE-EN 1097-2 specifications, respectively. The shape factor of the recycled concrete aggregate fraction was 6%, below 35% (maximum value allowed by the Structural Code). According to the Los Angeles coefficient, RCA obtained a maximum of 36%, less than 40%, a limiting value for structural concrete aggregates. Following the EN 12,620 specification, the shape factor and Los Angeles abrasion coefficient are classified as Fl15 and LA40, respectively. As mentioned above, the recycled aggregates were water cleansed. Consequently, after the washing process, all RCA aggregate fractions had a high moisture content in oversaturated conditions. Therefore, in order to control de water amount in concrete mixture, the moisture of aggregates was determined before their use in concrete production. Many researchers recommend the employment of recycled aggregates in highly humid conditions to produce concrete. However, it should not be saturated, as this could negatively affect the interface transition zone [ 38 , 39 ]. Nevertheless, in this case, due to the water washing process, the recycled aggregates were employed in wet conditions, sometimes even oversaturated. According to the obtained properties of RCA, the water-washed industrial treatment process guaranteed high quality RCA, adequate to be used in concrete. Other recycled aggregates treatments [ 40 ], only applied in laboratory scale, achieved also improvements in their physical properties. However, recycled aggregates which are required to be in a dry state or with medium humidity grade have been found up to be difficult to combine with the industrial water-washed treatment. 2.2. Methods Two phases of concrete production were conducted. Phase 1 included experimental laboratory work. For pavement-based layer construction, adequate mix proportions of concrete with 100% fine and coarse recycled aggregates (RAC concrete) were designed. The concrete was required to have acceptable workability (6–8 cm of slump test) 30 min after casting for adequate concrete placement. In addition, the produced concrete should have a minimum of 20 MPa compressive strength (strength in cylindrical specimens defined by Structural Code) after 28 days of curing. In phase 2, a RAC concrete pavement-base layer with a minimum of 20 MPa compressive strength (in cylindrical specimens) was built in Barcelona’s city centre using an adequate mix proportion; the fresh and hardened properties were determined. 2.2.1. Laboratory Work, Phase 1: Mix Proportions and Test Procedure All the concretes were produced employing 100% of fine and coarse RCA. 300 kg, 280 kg and 270 kg of cement were used in different mix proportions (see Table 4) to determine the minimum amount of cement needed to achieve adequate properties. In addition, the effective water/cement ratio was defined to establish the concretes’ mix proportions. While the effective water/cement ratio 0.55 was defined for the concretes produced with 300 kg and 285 kg of cement per m 3 of concrete, the value of 0.52–0.53 was defined for concrete produced with 270 kg of cement. The day before producing each concrete, all fraction of recycled aggregates were introduced into the oven at 100 ◦ C, and the aggregates’ humidity was determined to calculate the water amount to be added for concrete production and control its effective water/cement ratio. The average humidity values (and its standard deviation) of the FR1, FR2, CR1 and CR2 recycled aggregates were 12.2% (0.7%), 6.7% (0.4%), 6.1% (1%) and 4.6% (0.8%), respectively. The fine fractions (FR1 and FR2) were oversaturated when concretes were produced. Consequently, the water present on 24 Sustainability 2022,14, 708 the surface was considered part of effective water for concrete production. However, the coarse recycled aggregates (CR1 and CR2) had a high humidity but were not saturated. In this case, their effective absorption capacity was calculated (determined by submerging them in water for 20 min), and the determined water amount was added to the concrete to be absorbed by the CR1 and CR2 in order to maintain a constant effective water/cement ratio [ 5 ]. The multifunctional (P) and superplasticiser (S) chemical admixtures were used in different percentages to achieve the desired workability of 6–8 cm slump value at 30 min or later after casting. Table 4. Mix proportions of concrete mixtures. The values are given as weight (in dry condition) over the volume of concrete production (kg/m3). RAC-300 RAC-285-1 RAC-285-2 RAC-270-1 RAC-270-2 RCA-270-3 CEM II A-L 42.5 R 300 285 285 270 270 270 Efective w/c ratio 0.55 0.55 0.55 0.52 0.52 0.53 Total w/c ratio 0.91 0.91 0.90 0.90 0.89 0.94 Water 165 156.75 156.75 140.4 140.4 143.1 CR2 8/20 mm 682.6 694.3 694.3 713.2 713.2 710.8 CR1 4/10 mm 273.6 278.3 278.3 285.9 285.9 284.9 FR2 0/4 mm 589.9 600 600 616.4 616.4 614.3 FR1 0/2 mm 188.9 192.1 192.1 197.4 197.4 196.7 S * (%) 1 1 1 1.2 1 1.3 P * (%) 1.5 2 2.5 2.5 2.7 3 WORKABILITY (slump test in cm) t= 0 min 21.5 17 20 20 11 22 t= 30 min 7 - 3.5 - 6 18 t= 60 min - - - - - 6.5 * The amount of S and P used in concrete production is defined as per cent of the cement weight. All the produced concretes’ workability and slump value were determined following the UNE-EN 123350-2:2020 specifications. The slump values were determined immediately after concrete casting (t= 0 min) and 30 min or 60 min after concrete casting (t= 30 min or t= 60 min). Between 0 min (immediately after concrete casting) and 30 min or 60 min, the concrete mixture was kept in the mixer, which was stopped and covered with a plastic sheet until the test time elapsed. The concrete was then mixed for one minute before the slump was again measured. The concrete specimens were produced and cured following UNE-EN 12,390-2:2001 regulations and manually compacted using a steel rod. The concrete specimens were then covered with a plastic sheet and air-cured for the first 24 h. After 24 h of casting, the concrete specimens were demoulded and stored in the humidity room at 22 ◦ C and 95% humidity until tested. In the concretes’ hardened state, the compressive strength at 7, 28 and 56 days were determined following UNE-EN 123903:2020 specifications using cylindrical specimens of diameter Ø100 × 200 mm in length. In addition, the physical properties at 28 days were determined following UNE-EN 123907:2020 specifications using cubic specimens of 100 × 100 × 100 mm. Drying shrinkage was measured using concrete prismatic specimens of 70 × 70 × 285 mm, exposed to 20 ± 2 ◦ C and relative humidity 55 ± 5% for 56 days following UNE-EN 12390-16:2020 specifications. Each result represented the average of three measurements. 25 Sustainability 2022,14, 708 2.2.2. Pavement-Base Construction In May 2021, a 500 m long pavement-base layer with a 30-cm thickness (highlighted in green in Figure 4) in Passeig de Colom (PC) in Barcelona, Spain was constructed. Plain concrete with a minimum of 20 MPa compressive strength was manufactured using FR1, FR2, CR1 and CR2 fractions. In addition, more than 815 m 3 of washed recycled aggregates were employed in pavement-base layer construction. Sustainability 2022, 14, x FOR PEER REVIEW 9 of 22 FR2, CR1 and CR2 fractions. In addition, more than 815 m3 of washed recycled aggregates were employed in pavement-base layer construction. Figure 4. Section of pavement-base built using 100% recycled aggregate. Table 5 describes the three-mix proportions employed for pavement-base layer construction. The humidity of the aggregates was determined before producing the concretes, except for the first day RAC-300-PC1 concrete. The humidity was determined after concrete production and was higher than initially estimated. The average humidity values (and its standard deviation) of the FR1, FR2, CR1 and CR2 recycled aggregates were 21.5% (1.2%), 9.9% (0.4%), 6.4% (0.2%) and 4.9% (0.5%), respectively. The fine recycled aggregates (FR1 and FR2) had higher-humidity concretes produced in the laboratory. The concrete mixture used for pavement-base layer construction was designed with 300 kg of cement and an effective water/cement ratio of 0.52–0.53 to assure the minimum strength of 20 MPa. However, because the humidity of the aggregates used in RCA-300-PC1 concrete production was higher than the estimated values, the RAC-300-PC1 concrete was produced with an effective water/cement ratio of 0.59. The rest of the pavement-base layer production was constructed using the RCA-300-PC2 and RCA-300-PC3 concretes, with effective water/cement ratios of 0.52 and 0.53, respectively. Table 5. Mix proportions of the concrete produced. The values are given as weight (in humid conditions) over the volume of concrete production (kg/m3). RAC-300-PC1 RAC-300-PC2 RAC-300-PC3 CEM II A-L 42.5 300 300 300 TOTAL water 101.5 88.0 97.4 Efective w/c ratio 0.59 0.52 0.53 FR1 0/2 mm 246.4 253.3 244.8 FR2 0/4 mm 688.8 708.1 702.3 CR1 4/10 mm 274.1 281.8 280.5 CR2 8/20 mm 665.3 683.9 691.5 S ** (%) 1.05 + 0.2 1.05 + 0.2 1.05 + 0.2 P (%) 1 1 1 Figure 4. Section of pavement-base built using 100% recycled aggregate. Table 5 describes the three-mix proportions employed for pavement-base layer construction. The humidity of the aggregates was determined before producing the concretes, except for the first day RAC-300-PC1 concrete. The humidity was determined after concrete production and was higher than initially estimated. The average humidity values (and its standard deviation) of the FR1, FR2, CR1 and CR2 recycled aggregates were 21.5% (1.2%), 9.9% (0.4%), 6.4% (0.2%) and 4.9% (0.5%), respectively. The fine recycled aggregates (FR1 and FR2) had higher-humidity concretes produced in the laboratory. The concrete mixture used for pavement-base layer construction was designed with 300 kg of cement and an effective water/cement ratio of 0.52–0.53 to assure the minimum strength of 20 MPa. However, because the humidity of the aggregates used in RCA-300-PC1 concrete production was higher than the estimated values, the RAC-300-PC1 concrete was produced with an effective water/cement ratio of 0.59. The rest of the pavement-base layer production was constructed using the RCA-300-PC2 and RCA-300-PC3 concretes, with effective water/cement ratios of 0.52 and 0.53, respectively. Table 5. Mix proportions of the concrete produced. The values are given as weight (in humid conditions) over the volume of concrete production (kg/m3). RAC-300-PC1 RAC-300-PC2 RAC-300-PC3 CEM II A-L 42.5 300 300 300 TOTAL water 101.5 88.0 97.4 Efective w/c ratio 0.59 0.52 0.53 FR1 0/2 mm 246.4 253.3 244.8 FR2 0/4 mm 688.8 708.1 702.3 CR1 4/10 mm 274.1 281.8 280.5 CR2 8/20 mm 665.3 683.9 691.5 S ** (%) 1.05 + 0.2 1.05 + 0.2 1.05 + 0.2 P (%) 1 1 1 ** S and P: % of admixture for the cement weight. The second quantity of superplasticizer (+0.2) was added directly to the truck on-site to increase the workability of the concrete for placement in suitable conditions since the concrete arrived at the site one hour after its manufacture. 26 Sustainability 2022,14, 708 All theconcretes’workabilityandslumpvalues were determined on-site (see Figure 5a–c). Sustainability 2022, 14, x FOR PEER REVIEW 10 of 22 ** S and P: % of admixture for the cement weight. The second quantity of superplasticizer (+0.2) was added directly to the truck on-site to increase the workability of the concrete for placement in suitable conditions since the concrete arrived at the site one hour after its manufacture. All the concretes’ workability and slump values were determined on-site (see Figure 5a-c). The concrete mixtures were placed on-site directly from the truck (see Figure 6a). After compaction using a needle vibrator (see Figure 6b), the admixture of acrylic resinbased evaporation reducer, curing improvement admixture, was added to the concrete surface (see Figure 6c) to guarantee an adequate curing process. Figure 6 summarises the concrete laying process. Concrete specimens were fabricated to characterise the produced concretes. The concrete samples were manually compacted using a steel rod. The specimens were then covered with a plastic sheet and air-cured for the first 24 h at the worksite. After 24 h of casting, the concretes specimens were moved to the university laboratory, demoulded and stored in the humidity room until the required testing. The mechanical properties of compressive and flexural strength were determined. The compressive strength at 7, 14, 28 and 56 days was determined for cylindrical specimens of Ø100 mm × 200 mm and cubic specimens of 150 × 150 × 150 mm for 28 days. In addition, the flexural strength was determined using prismatic samples of 100 × 100 × 400 mm at 28 days of curing. The physical properties at 28 days were determined using cubic specimens of 100 × 100 × 100 mm. Finally, the durability properties of drying shrinkage and depth of penetration of water under pressure were determined. The drying shrinkage was determined using 70 × 70 × 285 mm specimens. Cylindrical specimens of Ø100 × 200 mm were used to calculate the penetration depth, following UNE-EN 12,390−8:2020 specification. Each result was recorded as the average of three measurements. RCA-300-PC1 RCA-300-PC2 RCA-300-PC3 (a) Slump: 15 cm (b) Slump: 8 cm (c) Slump: 10 cm Figure 5. On-site slump test determination (a) Slump: 15 cm (b) Slump: 8 cm (c) Slump: 10 cm (a) (b) (c) Figure 6. On-site concrete laying (a), compaction (b) and curing process (c) of the concrete. Figure 5. On-site slump test determination. The concrete mixtures were placed on-site directly from the truck (see Figure 6a). After compaction using a needle vibrator (see Figure 6b), the admixture of acrylic resin-based evaporation reducer, curing improvement admixture, was added to the concrete surface (see Figure 6c) to guarantee an adequate curing process. Figure 6 summarises the concrete laying process. Sustainability 2022, 14, x FOR PEER REVIEW 10 of 22 ** S and P: % of admixture for the cement weight. The second quantity of superplasticizer (+0.2) was added directly to the truck on-site to increase the workability of the concrete for placement in suitable conditions since the concrete arrived at the site one hour after its manufacture. All the concretes’ workability and slump values were determined on-site (see Figure 5a-c). The concrete mixtures were placed on-site directly from the truck (see Figure 6a). After compaction using a needle vibrator (see Figure 6b), the admixture of acrylic resinbased evaporation reducer, curing improvement admixture, was added to the concrete surface (see Figure 6c) to guarantee an adequate curing process. Figure 6 summarises the concrete laying process. Concrete specimens were fabricated to characterise the produced concretes. The concrete samples were manually compacted using a steel rod. The specimens were then covered with a plastic sheet and air-cured for the first 24 h at the worksite. After 24 h of casting, the concretes specimens were moved to the university laboratory, demoulded and stored in the humidity room until the required testing. The mechanical properties of compressive and flexural strength were determined. The compressive strength at 7, 14, 28 and 56 days was determined for cylindrical specimens of Ø100 mm × 200 mm and cubic specimens of 150 × 150 × 150 mm for 28 days. In addition, the flexural strength was determined using prismatic samples of 100 × 100 × 400 mm at 28 days of curing. The physical properties at 28 days were determined using cubic specimens of 100 × 100 × 100 mm. Finally, the durability properties of drying shrinkage and depth of penetration of water under pressure were determined. The drying shrinkage was determined using 70 × 70 × 285 mm specimens. Cylindrical specimens of Ø100 × 200 mm were used to calculate the penetration depth, following UNE-EN 12,390−8:2020 specification. Each result was recorded as the average of three measurements. RCA-300-PC1 RCA-300-PC2 RCA-300-PC3 (a) Slump: 15 cm (b) Slump: 8 cm (c) Slump: 10 cm Figure 5. On-site slump test determination (a) Slump: 15 cm (b) Slump: 8 cm (c) Slump: 10 cm (a) (b) (c) Figure 6. On-site concrete laying (a), compaction (b) and curing process (c) of the concrete. Figure 6. On-site concrete laying (a), compaction (b) and curing process (c) of the concrete. Concrete specimens were fabricated to characterise the produced concretes. The concrete samples were manually compacted using a steel rod. The specimens were then covered with a plastic sheet and air-cured for the first 24 h at the worksite. After 24 h of casting, the concretes specimens were moved to the university laboratory, demoulded and stored in the humidity room until the required testing. The mechanical properties of compressive and flexural strength were determined. The compressive strength at 7, 14, 28 and 56 days was determined for cylindrical specimens of Ø100 mm × 200 mm and cubic specimens of 150 × 150 × 150 mm for 28 days. In addition, the flexural strength was determined using prismatic samples of 100 × 100 × 400 mm at 28 days of curing. The physical properties at 28 days were determined using cubic specimens of 100 ×100 ×100 mm. Finally, the durability properties of drying shrinkage and depth of penetration of water under pressure were determined. The drying shrinkage was determined using 70 ×70 ×285 mm specimens. Cylindrical specimens of Ø100 × 200 mm were used to calculate the penetration depth, following UNE-EN 12,390 − 8:2020 specification. Each result was recorded as the average of three measurements. 27 Sustainability 2022,14, 708 shrinkage value of pavement concretes. They too sprayed a liquid curing compound on the finished surfaces after finishing. The high drying shrinkage limited the use of RAC in structural applications due to two effects: (1) excessive shrinkage deformation could endanger the safety of the structure because shrinkage of concrete plays a significant role in the design of the service limit state of structural members [ 33 , 48 , 52 ]; and (2) higher shrinkage may cause cracks. This could affect the overall performance of concrete and enable the ingress of harmful substances, resulting in the corrosion of structural concrete reinforcement [ 5 ]. However, the plain concrete pavement-base this risk does not occur as it is not reinforced. 5. Conclusions The following conclusions are based on the results of our study of concrete made with 100% coarse and fine RCA for a pavement-base layer: • The water-washed RCA achieved type A category, aggregates for concrete, adequate for pavement-base layer construction. In addition, the coarse and fine RCA fractions achieved an absorption capacity lower than 7%, and their physical and mechanical properties and chemical components fulfilled the requirements for use in structural concrete. • The properties of the pavement-base layer concrete produced on the worksite were similar to those obtained in the laboratory. Consequently, the laboratory results were validated for high-scale production. • All recycled concrete achieved adequate initial workability. However, to achieve an extended slump value (minimum for 30 min), a value of 3% multifunctional admixture plus 1–1.2% superplasticiser must be used in concrete production. • On the worksite, a lower chemical admixture was employed, causing a dry consistency, and requiring 0.20% superplasticiser. • All concretes achieved the required strength of 20 MPa. The concrete produced with 270 kg of cement per m 3 and a water/cement ratio of 0.53 resulted in the best properties with the lowest environmental impact. • The concretes presented a high absorption capacity. However, the water penetration depth under pressure value was below the maximum limit established by the structural code when the recycled concretes were produced with a water/cement ratio of 0.53 independent of the amount of cement used. • The drying shrinkage was high due to the employment of 100% of recycled aggregate concrete. Although there was no cracking in the concrete measured in the laboratory specimens, it is possible that the concrete could suffer high strain in low humidity days. However, pavement-base case is a non-structural plain concrete and consequently, problems with deformation and cracking to ingress harmful substances, resulting in corrosion cannot happen. The water-washed recycled aggregates do not include filler or any chemical components. In addition, they have good physical and mechanical properties for use in structural concrete production. The employment of 100% coarse and fine RCA in concrete production causes a considerable increase in drying shrinkage. This could increase deformation, significantly reducing the service life of structural members and the risk of cracking, enabling the ingress of harmful substances. However, non-structural elements do not have those limitations, and they allow the massive volume of recycled aggregates validated in this case study to be employed. The authors believe it is a straightforward, simple way to re-circulate construction and demolition waste. Author Contributions: Conceptualization, M.E. and M.Á.P.; methodology, M.E., M.K. and C.G.; validation, M.E., M.K., C.G. and M.Á.P.; investigation, M.E., M.K. and C.G.; resources, M.E. and M.Á.P.; writing—original draft preparation, M.E.; writing—review and editing, M.E.; project administration, M.E.; funding acquisition, M.E. and M.Á.P. All authors have read and agreed to the published version of the manuscript. 34 Sustainability 2022,14, 708 Funding: This research received no external funding. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. Acknowledgments: The authors thank Ajuntament de Barcelona (Barcelona city council), Bimsa and SBS Simón i Blanco for their courage and support in working with recycled aggregate concrete. The first author also wants the staff of the Laboratory of Technology of Structures and Materials “Lluis Agulló” of the UPC for their support. Conflicts of Interest: The authors declare no conflict of interest. References 1. Tam, V.W.Y.; Soomro, M.; Evangelista, A.C.J. A review of recycled aggregate in concrete applications (2000–2017). Constr. Build. Mater. 2018,172, 272–292. [CrossRef] 2. European Statistics-Eurostat. Energy, Transport and Environment Statistics 2020 Edition; Publications Office of the European Union: Luxembourg, 2020; ISBN 9789276207375. 3. European Commission. Communication from the Commission to the European parliament, the council, the European Economic and Social Committee and the Committee of the regions. Next steps for a sustainable European future European action for sustainability, Strasbourg, France, 2016. Available online: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=COM%3A201 6%3A739%3AFIN (accessed on 6 January 2022). 4. Plaza, P.; del Bosque, I.S.; Frías, M.; de Rojas, M.S.; Medina, C. Use of recycled coarse and fine aggregates in structural eco-concretes. Physical and mechanical properties and CO2 emissions. Constr. Build. Mater. 2021,285, 122926. [CrossRef] 5. Neville, A.M.; Neville, A.M. Properties of Concrete; Pearson Education Limited: London, UK, 2011; ISBN 9780273755807. 6. Renan Sorato, S.P.; Venkateswarlu, B. Recycled aggregate concrete; an overview. J. Struct. Eng. 2016,18, 67–75. 7. Nwakaire, C.M.; Yap, S.P.; Onn, C.C.; Yuen, C.W.; Ibrahim, H.A. Utilisation of recycled concrete aggregates for sustainable highway pavement applications; a review. Constr. Build. Mater. 2019,235, 117444. [CrossRef] 8. Selvam, M.; Debbarma, S.; Singh, S.; Shi, X. Utilization of alternative aggregates for roller compacted concrete pavements—A state - of-the-art review. Constr. Build. Mater. 2021,317, 125838. [CrossRef] 9. Sadati, S.; Khayat, K. Field performance of concrete pavement incorporating recycled concrete aggregate. Constr. Build. Mater. 2016,126, 691–700. [CrossRef] 10. Cuttell, G.D.; Snyder, M.B.; Vandenbossche, J.M.; Wade, M.J. Performance of Rigid Pavements Containing Recycled Concrete Aggregates. Transp. Res. Rec. J. Transp. Res. Board 1997,1574, 89–98. [CrossRef] 11. Nassar, R.; Soroushian, P. Use of recycled aggregate concrete in pavement construction. J. Solid Waste Technol. Manag. 2016 ,42, 137–144. [CrossRef] 12. Gress, D.L.; Snyder, M.B.; Sturtevant, J.R. Performance of Rigid Pavements Containing Recycled Concrete Aggregate. Transp. Res. Rec. J. Transp. Res. Board 2009,2113, 99–107. [CrossRef] 13. Silva, R.V.; de Brito, J.; Dhir, R.K. Use of recycled aggregates arising from construction and demolition waste in new construction applications. J. Clean. Prod. 2019,236, 117629. [CrossRef] 14. Poon, C.S.; Chan, D. The use of recycled aggregate in concrete in Hong Kong. Resour. Conserv. Recycl. 2007 ,50, 293–305. [CrossRef] 15. Zhang, H.; Zhao, Y. Performance of Recycled Aggregate Concrete in a Real Project. Adv. Struct. Eng. 2014 ,17, 895–906. [CrossRef] 16. Xiao, J.; Wang, C.; Ding, T.; Nezhad, A.A. A recycled aggregate concrete high-rise building: Structural performance and embodied carbon footprint. J. Clean. Prod. 2018,199, 868–881. [CrossRef] 17. Chen, W.; Jin, R.; Xu, Y.; Wanatowski, D.; Li, B.; Yan, L.; Pan, Z.; Yang, Y. Adopting recycled aggregates as sustainable construction materials: A review of the scientific literature. Constr. Build. Mater. 2019,218, 483–496. [CrossRef] 18. Pedro, D.; de Brito, J.; Evangelista, L. Influence of the use of recycled concrete aggregates from different sources on structural concrete. Constr. Build. Mater. 2014,71, 141–151. [CrossRef] 19. Etxeberria, M.; Mari, A.; Vázquez, E. Recycled aggregate concrete as structural material. Mater. Struct. 2006 ,40, 529–541. [CrossRef] 20. Kirthika, S.K.; Singh, S.; Chourasia, A. Alternative fine aggregates in production of sustainable concrete—A review. J. Clean. Prod. 2020,268, 122089. [CrossRef] 21. López-Gayarre, F.; Serna, P.; Domingo-Cabo, A.; Serrano-López, M.; López-Colina, C. Influence of recycled aggregate quality and proportioning criteria on recycled concrete properties. Waste Manag. 2009,29, 3022–3028. [CrossRef] 22. Miren, E.; Enric, V.; Marí, A.R. Microstructure analysis of hardened recycled aggregate concrete. Mag. Concr. Res. 2006 ,58, 683–690. 23. Hansen, T.C. Recycling of Demolished Concrete and Masonry; E&FN Spon: London, UK, 1992. 24. Khatib, J.M. Properties of concrete incorporating fine recycled aggregate. Cem. Concr. Res. 2005,35, 763–769. [CrossRef] 35 Sustainability 2022,14, 708 25. Bogas, J.A.; de Brito, J.; Ramos, D. Freeze-thaw resistance of concrete produced with fine recycled concrete aggregates. J. Clean. Prod. 2016,115, 294–306. [CrossRef] 26. Lavado, J.; Bogas, J.; de Brito, J.; Hawreen, A. Fresh properties of recycled aggregate concrete. Constr. Build. Mater. 2020 , 233, 117322. [CrossRef] 27. Nedeljkovi´c, M.; Visser, J.; Šavija, B.; Valcke, S.; Schlangen, E. Use of fine recycled concrete aggregates in concrete: A critical review. J. Build. Eng. 2021,38, 102196. [CrossRef] 28. Sasanipour, H.; Aslani, F. Durability properties evaluation of self-compacting concrete prepared with waste fine and coarse recycled concrete aggregates. Constr. Build. Mater. 2019,236, 117540. [CrossRef] 29. Tobori, N.; Hosoda, T.; Kasami, H. Properties of Superplasticized Concrete Containing Recycled Fine Aggregate. In International Conference on High performance Concrete, and Performance and Quality of Concrete Structures; Farmington Hills: Gramado, RS, Brazil, 1999. 30. Pereira, P.; Evangelista, L.; de Brito, J. The effect of superplasticizers on the mechanical performance of concrete made with fine recycled concrete aggregates. Cem. Concr. Compos. 2012,34, 1044–1052. [CrossRef] 31. Evangelista, L.; de Brito, J. Durability performance of concrete made with fine recycled concrete aggregates. Cem. Concr. Compos. 2010,32, 9–14. [CrossRef] 32. Wang, Y.; Liu, F.; Xu, L.; Zhao, H. Effect of elevated temperatures and cooling methods on strength of concrete made with coarse and fine recycled concrete aggregates. Constr. Build. Mater. 2019,210, 540–547. [CrossRef] 33. Zhang, H.; Wang, Y.; Lehman, D.E.; Geng, Y.; Kuder, K. Time-dependent drying shrinkage model for concrete with coarse and fine recycled aggregate. Cem. Concr. Compos. 2019,105, 103426. [CrossRef] 34. Pacheco-Torgal, F.; Ding, Y.; Colangelo, F.; Tuladhar, R.; Koutamanis, A. Advances in Construction and Demolition Waste Recycling. Management, Processing and Enviromental Assessment, 1st ed.; Elsevier: Amsterdam, The Netherlands, 2020. 35. H-ZERO. 2021. Available online: https://www.hercalzero.es/h-zero-planta-rcd/ (accessed on 6 January 2022). 36. Relaciones con las Cortes y Memoria Democrática; Ministry of Presidential. Codigo Estructural, España (Structural CodeConcrete). 2021. Available online: https://www.boe.es/eli/es/rd/2021/06/29/470 (accessed on 6 January 2022). 37. de Brito, J.; Agrela, F.; Silva, R.V. Legal Regulations of Recycled Aggregate Concrete in Buildings and Roads. In New Trends in Eco-efficient and Recycled Concrete; Elsevier: Amsterdam, The Netherlands, 2019; pp. 509–526. [CrossRef] 38. Poon, C.; Shui, Z.; Lam, L. Effect of microstructure of ITZ on compressive strength of concrete prepared with recycled aggregates. Constr. Build. Mater. 2004,18, 461–468. [CrossRef] 39. Evangelista, L.; Gueded, M. Microstructural Studies on Recycled Aggregate Concrete. In New Trends in Eco-Efficient and Recycled Concrete; Elsevier: Amsterdam, The Netherlands, 2019; pp. 425–451. 40. Kazmi, S.M.S.; Munir, M.J.; Wu, Y.-F.; Patnaikuni, I.; Zhou, Y.; Xing, F. Effect of recycled aggregate treatment techniques on the durability of concrete: A comparative evaluation. Constr. Build. Mater. 2020,264, 120284. [CrossRef] 41. Revilla-Cuesta, V.; Faleschini, F.; Zanini, M.A.; Skaf, M.; Ortega-López, V. Porosity-based models for estimating the mechanical properties of self-compacting concrete with coarse and fine recycled concrete aggregate. J. Build. Eng. 2021 ,44, 103425. [CrossRef] 42. Ministerio de Fomento, E. PG-3 Pliego de Prescripciones Técnicas Generales Para Obras de Carreteras y Puentes; Ministry of Public Works: Madrid, Spain, 2015. Available online: https://apps.fomento.gob.es/CVP/handlers/pdfhandler.ashx?idpub=ICW020 (accessed on 6 January 2022). 43. Etxeberria, M.; Vázquez, E.; Mari, A.; Barra, M. Influence of amount of recycled coarse aggregates and production process on properties of recycled aggregate concrete. Cem. Concr. Res. 2007,37, 735–742. [CrossRef] 44. Thomas, J.; Thaickavil, N.N.; Wilson, P. Strength and durability of concrete containing recycled concrete aggregates. J. Build. Eng. 2018,19, 349–365. [CrossRef] 45. Etxeberria, M.; Fernandez, J.M.; Limeira, J. Secondary aggregates and seawater employment for sustainable concrete dyke blocks production: Case study. Constr. Build. Mater. 2016,113, 586–595. [CrossRef] 46. Mcdonald, D.B.; Brooks, J.J.; Burg, R.G.; Daye, M.A.; Gardner, N.J.; Novak, L.C. Report on Factors Affecting Shrinkage and Creep of Hardened Concrete Reported by ACI Committee 209; American Concrete Institute (ACI): Farmington Hills, MI, USA, 2014; pp. 1–12. 47. Pedro, D.; de Brito, J.; Evangelista, L. Structural concrete with simultaneous incorporation of fine and coarse recycled concrete aggregates: Mechanical, durability and long-term properties. Constr. Build. Mater. 2017,154, 294–309. [CrossRef] 48. Mao, Y.; Liu, J.; Shi, C. Autogenous shrinkage and drying shrinkage of recycled aggregate concrete: A review. J. Clean. Prod. 2021 , 295, 126435. [CrossRef] 49. Tahar, Z.-E.; Ngo, T.-T.; Kadri, E.H.; Bouvet, A.; Debieb, F.; Aggoun, S. Effect of cement and admixture on the utilization of recycled aggregates in concrete. Constr. Build. Mater. 2017,149, 91–102. [CrossRef] 50. de Souza, A.M.; de Lima, G.E.S.; Nalon, G.H.; Lopes, M.M.S.; Júnior, A.L.D.O.; Lopes, G.J.R.; Olivier, M.J.d.A.; Pedroti, L.G.; Ribeiro, J.C.L.; de Carvalho, J.M.F. Application of the desirability function for the development of new composite eco-efficiency indicators for concrete. J. Build. Eng. 2021,40, 102374. [CrossRef] 51. Thomas, C.; Setién, J.; Polanco, J.A.; Alaejos, P.; De Juan, M.S. Durability of recycled aggregate concrete. Constr. Build. Mater. 2013 , 40, 1054–1065. [CrossRef] 52. Silva, R.; de Brito, J.; Dhir, R. Prediction of the shrinkage behavior of recycled aggregate concrete: A review. Constr. Build. Mater. 2015,77, 327–339. [CrossRef] 36