Environmental implications of concrete industry practices in Cameroon: A life cycle approach

 Corresponding author: Nimpa Giscard Desting Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0. Environmental implications of concrete industry practices in Cameroon: A life cycle approach Nimpa Giscard Desting *, Deodonne Kunwufne, Minane Jacques Rémy and Tinchie Donald National Advanced School of Engineering, Department of Civil Engineering and Urban Planning; University of Yaoundé I – Cameroon. Global Journal of Engineering and Technology Advances, 2025, 23(01), 347-362 Publication history: Received on 07 March 2025; revised on 23 April 2025; accepted on 25 April 2025 Article DOI: https://doi.org/10.30574/gjeta.2025.23.1.0138 Abstract Rapid urbanization in sub-Saharan Africa is driving a sharp increase in concrete use, raising significant environmental concerns. This study evaluates the environmental impacts of concrete production in Cameroon through a life cycle assessment (LCA), with the aim of identifying effective strategies for impact reduction. The analysis is based on primary data from 18 concrete batching plants across major urban centers, combined with national-level secondary data. It follows ISO 14040 standards and applies the IMPACT 2002+ method within SimaPro 9.0. The functional unit is 1 m³ of ready-mix concrete. Cement production accounts for the majority of impacts, contributing over 80% of greenhouse gas emissions (347 kg CO₂-eq/m³ out of 427 kg CO₂-eq/m³), 57% of non-renewable energy use, and most human health effects (168 DALYs/year). Clinker content is the main driver of emissions, while electricity use and transport distances have smaller effects. Results related to human toxicity vary across impact assessment methods. By combining empirical data with regional assumptions, this study addresses a gap in LCA research for emerging economies. It highlights the need for clinker substitution, improved energy efficiency, and optimized logistics to reduce the environmental footprint of concrete. Keywords: Concrete industry; Cameroon; Life Cycle Assessment; cement production; Carbon Footprint; building materials 1. Introduction Concrete remains the cornerstone of modern construction, with global production surpassing 30 billion tonnes annually, making it the most consumed man-made material by volume [1]. Its extensive use in both industrialized and rapidly developing regions reflects an accelerating demand for resilient infrastructure, particularly in the face of urbanization, demographic shifts, and climate adaptation imperatives [2, 3]. However, the environmental burden of concrete production is considerable. Cement manufacturing, its most energy and emissions intensive component, is alone responsible for approximately 7–8% of global anthropogenic CO₂ emissions, largely due to the calcination of limestone and the combustion of fossil fuels during clinker production [4, 5]. The construction sector’s contribution to climate change, resource depletion, and ecosystem degradation has intensified calls for sustainability-driven transformation, particularly in emerging economies where urban growth is most rapid [6, 7, 8]. Life Cycle Assessment (LCA), standardized by ISO 14040 and ISO 14044, has emerged as the principal methodological framework for evaluating environmental impacts across the entire life cycle of building materials, from raw material extraction to end-of-life management [9, 10, 11]. Yet, despite LCA’s growing application in high-income contexts, its deployment in sub-Saharan Africa remains limited due to insufficient regional life cycle inventory (LCI) data and fragmented production systems [12, 13, 14]. Global Journal of Engineering and Technology Advances, 2025, 23(01), 347-362 348 In the Cameroonian context, concrete production is undergoing rapid expansion driven by large-scale public infrastructure initiatives and rising housing demand [15, 16]. However, the industry is characterized by a dual structure: formal, industrial-scale batching plants with relatively advanced technologies coexist with informal, decentralized mixing practices in peri-urban and rural settings. This heterogeneity leads to inconsistent quality control, variable environmental performance, and a general lack of traceability in material flows. Compounded by an absence of reliable, geographically contextualized life cycle inventory (LCI) datasets, the environmental implications of concrete production in Cameroon remain poorly understood. Addressing this knowledge gap is critical not only for national sustainability planning but also for contributing to global decarbonization goals within the construction sector [17]. As environmental impacts of concrete vary significantly with local energy mixes, raw material sourcing, and production technologies, context-specific LCA studies are essential for generating actionable insights [18]. Furthermore, aligning such research with advanced LCA platforms and multi-impact methods, such as IMPACT 2002+, ReCiPe, or Eco-Indicator 99, can enhance methodological rigor and support robust decision-making frameworks [19]. This study seeks to develop a comprehensive, locally calibrated Life Cycle Assessment of concrete production in Cameroon. By leveraging empirical field data, stakeholder engagement, and advanced modeling techniques, it aims to identify critical environmental hotspots, examine the implications of technological and logistical choices, and inform pathways toward low-carbon, resource-efficient construction practices in the region. 2. Methodological framework of the LCA 2.1. Brief overview of the concrete industry in Cameroon This section provides a detailed overview of the concrete industry in Cameroon, with a focus on the sourcing and processing of raw materials as well as the production methods commonly employed across the country. Particular attention is given to the technological infrastructure, production systems, and key organizational actors shaping the sector. 2.1.1. Mapping the concrete production sector in Cameroon A survey identified 18 operational concrete batching plants across multiple regions, including urban centers like Yaounde, Douala, Bafoussam, Garoua, and Maroua. To illustrate the industrial landscape, Table 1 presents a summary of the main concrete production companies identified during field investigations, including their geographic distribution and operational status. Table 1 Concrete batching plants identified in Cameroon N° Identified concrete batching plants Geographic distribution Operational status 1 Cimencam Centre - Yaounde Operational – Under construction 2 KT&CO Centre - Yaounde Operational – Fixed plant 3 Cameroun Concentre Company Sarl (CMCC) Centre - Yaounde Operational – Fixed plant 4 Béton Construction et Carrière (BCC) Centre - Yaounde Operational – Fixed plant 5 Djemo BTP Centre - Yaounde Operational – Under construction 6 Alpha Beton Centre - Obala Operational – Fixed plant 7 Razel Cameroun Centre - NTUI Operational – Fixed plant 8 Cimencam Littoral - Douala Operational – Under construction 9 Goker Littoral - Douala Operational – Fixed plant 10 Les Bâtisseurs Réunis Littoral - Douala Operational – Fixed plant 11 Besix Cameroun Sarl Littoral - Douala Operational – Under construction 12 Béton Construction et Carrière (BCC) Littoral - Douala Operational – Fixed plant Global Journal of Engineering and Technology Advances, 2025, 23(01), 347-362 349 13 Cameroon Concrete Company (CCC) Littoral - Dibamba Operational – Fixed plant 14 Kalfrelec Littoral - Dibamba Operational – Fixed & Mobile plant 15 CIMAF Ouest - Bafoussam Operational – Fixed plant 16 CIMAF Nord - Garoua Operational – Fixed plant 17 CIMAF Extrême Nord - Maroua Operational – Fixed plant 18 Dangote Est - Bertoua Operational – Fixed plant 2.1.2. Locally applied concrete manufacturing technologies Field investigations revealed that local concrete production methods differ slightly across facilities, depending on their equipment and operational practices. These plants are broadly categorized into fixed and mobile types, with all surveyed facilities being fixed installations—except for Kalfrelec, which also operates a mobile unit. Fixed batching plants generally include a cement silo with filtration, aggregate storage and dosing systems, weighing equipment, a water supply unit, and a concrete mixer. Most plants utilize modern, sealed mixers to comply with environmental standards, enhancing both product quality and emission control. 2.1.3. Local production process The concrete production process observed at the surveyed plants follows standardized stages: • Material dosing: Cement, aggregates, water, and admixtures are measured based on predefined mix designs; • Mixing: The ingredients are homogenized in high-efficiency mixers, either in dry or wet form; • Quality control: Regular sampling is performed to test properties such as compressive strength, water content, and consistency; • Delivery: The ready-mix concrete is transported to construction sites using rotating drum trucks to prevent material segregation. Mobile batching plants follow a similar production logic but offer greater logistical flexibility, particularly for remote or temporary construction sites. Their use is increasing in response to infrastructure development in less accessible regions. In addition to industrial-scale production, concrete is also frequently prepared on-site by individual workers or smallscale contractors. In such cases, raw materials are manually dosed and mixed directly at the construction site using basic equipment, such as small drum mixers or, occasionally, manual tools. While this informal approach is widely practiced for small to medium-scale projects, it often lacks rigorous quality control and adherence to environmental standards. 2.2. Concrete industry LCA in Cameroon 2.2.1. Objectives and Scope of the Study This study assesses the environmental impact of Cameroon’s concrete industry using a life cycle assessment (LCA) approach, with the aim of identifying key impact sources and informing more sustainable construction practices. As concrete production expands across sub-Saharan Africa due to rapid urbanization, Cameroon faces growing environmental challenges linked to raw material extraction, processing, and transport, particularly across diverse and informal production systems. The functional unit selected is 1 m³ of ready-mix concrete, a standard reference commonly used in LCA studies to evaluate environmental impacts in relation to structural performance [20, 21, 22]. System boundaries were defined based on field data, encompassing raw material extraction, processing, transport, concrete production, and delivery to construction sites. Key inputs include cement, aggregates, water, and admixtures. Transport over long distances and variable infrastructure contributes significantly to fuel consumption and emissions. Concrete mixing involves controlled dosing to ensure structural performance, while time-sensitive delivery under local climatic conditions adds further environmental pressure. The system is modeled following ISO 14040, distinguishing input and output flows across each elementary process. Global Journal of Engineering and Technology Advances, 2025, 23(01), 347-362 350 This research highlights the need for regionalized LCA approaches in areas with distinct production practices. Given that cement activities contribute to over 8% of global CO₂ emissions [20], the findings could inform national strategies to reduce the environmental impact of the construction sector in Cameroon and similar regions. 2.2.2. Life Cycle Inventory Approach The inventory modeling drew on multiple sources: primary data from site visits, secondary data from relevant literature, and context-specific assumptions based on national practices. Concrete production volumes were estimated from the average daily outputs reported by the surveyed plants, as presented in Table 2. Table 2 Daily production of the surveyed concrete plants Concrete plants Proposed formulation ranges Compressive strength (MPa) Typical use cases Average daily quantities (m³) Béton Construction et Carrières (BCC) B12 / B40 12 to 40 Small foundations, nonstructural works, all structural uses up to special structures 328 Razel – BEC, Douala 200 Razel – BEC, Mfou 190 Cameroon Concentre Company 230 Les Bâtisseurs Réunis B15 / B35 15 to 35 Foundations, slabs, beams, standard columns, multistory buildings 275 Kalfrelec 164 Goker 180 KT&CO 160 Cameroon Concrete Company (CCC) B20 / B40 20 to 40 From Slabs, beams, to bridges 190 Under Constructionᵃ B15 / B30 15 to 30 Foundations, slabs, beams, columns 825 Not Visitedᵇ 950 Total 3,692 ᵃ Plants under construction and nearly operational as observed during field visits. Three in particular, whose production is estimated based on that of Les Bâtisseurs Réunis, given their strong technological profile similarity. ᵇ This group includes the three CIMAF plants (West, North, Far North), the DANGOTE plant in the East, and Alpha Béton in Obala, which were not accessible. Their production is estimated based on that of Cameroon Concrete Company. The proportions of aggregates, water, and admixtures used in the mixes were determined from formulation data provided by these facilities, which are detailed in Table 3. Table 3 Mix proportions formulated by the concrete plants visited Concrete plant Mix Composition per Unit Volume (Kg/m³) Mix 1 Mix 2 Mix 3 Cement FA CA Water Cement FA CA Water Cement FA CA Water Les Bâtisseurs Réunis 200 800 1140 180 350 720 1180 180 450 735 1200 180 Kalfrelec 200 800 1140 170 350 725 1180 170 400 730 1200 170 Cameroun Concrete Company (CCC) 300 705 1166 180 350 720 1103 180 450 735 1135 180 KT&CO 250 700 1160 180 350 720 1100 180 450 735 1135 180 Béton Construction et Carrières (BCC) 300 705 1166 180 350 720 1103 180 450 735 1135 180 Global Journal of Engineering and Technology Advances, 2025, 23(01), 347-362 351 Goker 200 700 1140 175 350 720 1170 175 450 735 1200 175 Razel – BEC, Douala 300 750 1175 180 350 720 1190 180 450 735 1200 180 Razel – BEC, Mfou 300 750 1175 180 350 720 1190 180 450 735 1200 180 Cameroun Concentre Company (CMCC) 300 705 1166 180 350 720 1103 180 450 735 1135 180 FA = Fine Aggregates CA = Coarse Aggregates Further specifications regarding the types and dosages of admixtures are outlined in Table 4. Table 4 Admixture proportion added per unit volume in the surveyed concrete plants Concrete plant Type of admixtures used and quantity per unit volume (l/m³) Plasticizer Superplasticizer Retarder Accelerator Mix Mix Mix Mix 1 2 3 1 2 3 1 2 3 1 2 3 Les Bâtisseurs Réunis 4 4 4 4 4 4 4 4 4 4 4 4 Kalfrelec 4 4 4 4 4 4 4 4 4 4 4 4 Cameroun Concrete Company (CCC) 0 0 0 1,78 1,90 3 0 0 0 0 0 0 KT&CO 4 4 4 4 4 4 4 4 4 4 4 4 Béton Construction et Carrières (BCC) 4 4 4 4 4 4 4 4 4 4 4 4 Goker 3 3 3 3 3 3 3 3 3 3 3 3 Razel – BEC, Douala 4 4 4 4 4 4 4 4 4 4 4 4 Razel – BEC, Mfou 4 4 4 4 4 4 4 4 4 4 4 4 Cameroun Concentre Company (CMCC) 4 4 4 4 4 4 4 4 4 4 4 4 Finally, transport distances from raw material sources to concrete plants were measured, with variations linked to resource distribution and infrastructure availability, as shown in Table 5. Table 5 Supply distances for cement, aggregates, and admixtures Concrete plants Supply distances (Km) Cement (Km) Fine Aggregates (Km) Coarse Aggregates (Km) Admixtures (Km) Les Bâtisseurs Réunis 20 70 70 30 Kalfrelec 30 60 40 30 Cameroun Concrete Company (CCC) 20 50 40 25 KT&CO 10 10 10 10 Béton Construction et Carrières (BCC) 35 15 15 5 Goker 10 60 25 15 Razel – BEC, Douala 25 65 60 25 Razel – BEC, Mfou 50 5 5 25 Cameroun Concentre Company (CMCC) 25 5 5 5 Average distances (Km) 25 40 40 25 Global Journal of Engineering and Technology Advances, 2025, 23(01), 347-362 352 In cases where primary data were unavailable, reasonable assumptions were made to fill gaps and streamline the analysis. Specifically, this study assumes a constant population growth rate of 2.64% annually from 2021 to 2023, with an average household size of four. The proportion of new housing built with permanent materials (49.8% in 2014) is assumed to remain unchanged [23]. Concrete batching plants are assumed to be supplied by local water utilities, and among new constructions using site-mixed concrete, 25% are two-story building and 75% are single-story. Concrete is dosed at 350 kg/m³. The study focuses on small-scale residential construction, excluding large-scale projects. With a projected population of 28.6 million in 2023, this results in approximately 189,000 new households. By applying these assumptions and considering the growth of the middle class, concrete demand estimates are derived, as presented in Tables 6 and Table 7. Table 6 Concrete structural elements and volumes for the single-story model Structural elements Description Number and dimensions of concrete elements Required concrete volume (m³) Foundation Continuous strip footing, 15 cm thick and 20 cm high Footing cast along: 2×13.88 m + 2×7.89 m and 3×7.89 m + 2×5.2 m 2.32 Columns Columns with a height of 2.8 m 16 columns, cross-section: 15×15 cm 1.008 Tie beam (reinforced concrete ring beam) Tie beam along load-bearing walls, 15×15 cm Tie beam cast along: 2×13.88 m + 2×7.89 m and 3×7.89 m + 2×5.2 m 1.74 Septic tank slabs¹ Upper and lower slabs, 15 cm thick, for 3 septic tank chambers Slabs over 2×2 m×3 m 1.8 Total 6.868 ¹ The local sanitation system used is an individual on-site treatment system, consisting of three septic tank chambers and a soakaway pit. Table 6 presents the estimation for the usable concrete volume required for the construction of structural elements in a single-story dwelling, which is calculated to be 6.868 m³. Based on the assumptions made, the total volume required is accordingly calculated as: Vt1 = 189,073 × 49.8% × 6.868 × 75% = 485,009.68 m³. Moreover, Table 7 shows the estimation for the usable concrete volume required for the structural elements of a twostory dwelling. Table 7 Concrete elements specification and volume for two-story Model Structural elements Description Number and dimensions of concrete elements Required concrete volume (m³) Foundation Isolated footings, 15 cm thick 20 footings, each: 0.15 m × 0.45 m × 0.6 m 0.81 Ground floor columns Columns with a height of 3.8 m (up to footing) 24 columns, cross-section: 15 × 15 cm 2.052 Tie beam (reinforced concrete ring beam) Tie beam along load-bearing walls, 15 × 15 cm Total length: 80.86 m × 0.15 × 0.15 m 1.16 First floor columns Columns with a height of 2.8 m 26 columns, cross-section: 15 × 15 cm 1.638 Staircases Casting of 2 ramps and steps Dimensions: 2 × 1.175 m × 0.15 m × 7 m 2.4675 Septic tank slabs¹ Upper and lower slabs, 15 cm thick, for 3 septic tank chambers Slabs over 2 × 2 m × 3 m 1.8 Total 9.9275 The locally used sanitation system is an individual on-site system consisting of three septic tank chambers and a soakaway pit. Global Journal of Engineering and Technology Advances, 2025, 23(01), 347-362 353 This volume is estimated at 9.9275 m³. Based on the adopted assumptions, the total concrete volume is calculated as follows: Vt2 = 189,073 × 49.8% × 9.9275 × 25% = 233,689.26 m³ By integrating empirical data with context-specific assumptions, this life cycle inventory offers a realistic representation of concrete production in Cameroon and helps bridge a crucial gap in regional LCA data availability. Similar approaches are recommended by global frameworks such as ISO 14044 for settings lacking robust inventories [24], highlighting the value of local data collection in improving LCA accuracy in emerging economies. Based on the total volume previously determined, the quantities of raw materials required per functional unit (FU), as well as the corresponding annual totals, are presented in Table 8. Table 8 Annual total quantities of raw materials Material Process Quantity per FU (t) Annual total (t) Cement Extraction 0.35 656,003.229 Fine Aggregates Extraction 0.72 1,349,492.357 Coarse Aggregates Extraction 1.15 2,155,439.181 Water Extraction 0.18 337,373.089 Additives Extraction 0.016 29,988.720 The life cycle inventory (LCI) was established using data collected from key industry stakeholders, along with calculations informed by earlier assumptions. In addition to these, several methodological considerations were integrated into the process. First, for raw material extraction, input-output data for cement production were drawn from a scientific study conducted in Zimbabwe [25] and from Petek et al. [26]. Data related to the extraction and use of chemical additives were taken from Petek [27]. Second, the inventory data related to water extraction and distribution were sourced from a model developed by a local utility in South Africa and incorporated into the SimaPro software. Third, transport-related emissions were estimated based on average fuel consumption, assumed to be 35 liters per 100 kilometers, according to field interviews with drivers. Additionally, it was considered that engine oil levels decrease by approximately 2 liters every 100 km. Transportation modes were differentiated based on material type: semi-trailers (44 tonnes) were used for cement, 28tonne trucks for aggregates and additives, and 15 m³ mixer trucks for ready-mixed concrete. An average transport distance of 50 km was assumed across all materials. Once consolidated, these data enabled the development of a normalized inventory per functional unit, which serves as the basis for emission calculations in the Cameroonian concrete industry, as presented in Table 9. Table 9 Activity data per FU for emissions in Cameroonian concrete industry Life cycle stage Unit Value Life cycle stage Unit Value Raw material extraction and production Raw material transportation Cement production Cement transport Input Diesel kg 0.0585 Clinker kg 315.875 Lubricant kg 0.0036 Gypsum kg 16.625 Aggregate transport Electricity kWh 13.16 Diesel kg 0.785 Output Lubricant kg 0.048 Cement kg 350 Admixture transport Global Journal of Engineering and Technology Advances, 2025, 23(01), 347-362 354 Aggregate production Diesel kg 0.0042 Input Lubricant kg 0.00024 Diesel kg 1.762 Concrete production Output Input: Fine Aggregates kg 720 Cement kg 350 Coarse Aggregates kg 1150 Fine Aggregates kg 720 Admixture Production Coarse Aggregates kg 1150 Input Admixtures kg 16 Electricity kWh 5.28 Water kg 180 Output Electricity kWh 3.059 Plasticizer kg 4 Output Superplasticizer kg 4 Concrete m³ 1 Retarder kg 4 Concrete transportation Accelerator kg 4 Diesel kg 0.604 Solid Waste kg 0.008 Lubricant kg 0.015 2.2.3. Life cycle impact assessment (LCIA) methodology The Life Cycle Impact Assessment (LCIA) was carried out using SimaPro 9.0 software, implementing the IMPACT 2002+ method. This integrated approach combines mid-point and end-point modeling, enabling the characterization and damage assessment of various environmental impact categories associated with concrete production processes. Characterization was performed by applying the mid-point factors embedded in IMPACT 2002+ to the inventory data compiled in the previous phase. This step covered fifteen mid-point categories, including but not limited to human toxicity (carcinogenic and non-carcinogenic), respiratory effects, ionizing radiation, aquatic and terrestrial ecotoxicity, ozone layer depletion, acidification, eutrophication, land occupation, climate change, and resource depletion. Damage assessment was subsequently performed by aggregating midpoint scores into four main damage categories: human health, ecosystem quality, climate change, and resource availability. This was achieved using the damage factors defined by Jolliet et al. [28] and Baidai [29]. To evaluate the robustness of the selected impact assessment method, a sensitivity analysis was carried out. This involved comparing the results obtained using IMPACT 2002+ with those derived from the Eco-Indicator 99 (H) method. The comparison focused on the relative contributions of each life cycle stage to the various impact categories, allowing for an assessment of methodological consistency and reliability. All characterization and damage modeling steps followed standardized LCIA procedures and employed default methodological parameters provided by SimaPro, unless stated otherwise 3. Results and discussion 3.1. Characterization and damage scores of concrete production in Cameroon Based on the inventory data provided in the previous section, the calculation of environmental impact categories was carried out using the SimaPro software, applying the integrated impact assessment methodology, Impact 2002+. Table 10 reports the mid-point characterization scores across all life cycle stages. Subsequently, by applying the characterization factors detailed in Table 10 to these scores, the damage scores corresponding to the various mid-point impact categories were derived, as presented in Table 11. Global Journal of Engineering and Technology Advances, 2025, 23(01), 347-362 355 3.2. Sensitivity analysis The sensitivity analyses presented here focus on verifying the robustness of the IMPACT 2002+ method and examining various process parameters in the study. 3.2.1. Sensitivity analysis of the assessment method A sensitivity analysis was performed by comparing the IMPACT 2002+ method with the Eco-Indicator 99 (H) method. Table 12 shows the percentage contribution of each life cycle phase to the various impact categories. It was observed that only the carcinogenic human toxicity category exhibits inconsistencies across the different phases of the process. A reversal of trends is noted in this category. According to the IMPACT 2002+ method, the phase of adjuvant production has the highest harmful influence, estimated at 59%, followed by the cement production phase at 39.9%, while water production is the least harmful, contributing only 0.2%. In contrast, in the Eco-Indicator 99 method, the cement production phase has the greatest harmful impact at 72.4%, followed by the adjuvant production phase at 11.8%, and water production remains the least harmful at 0.1%. For the other categories, the results are very similar between the two methods, and in some cases, the results are identical, such as for acidification and eutrophication. This sensitivity analysis indicates that, overall, the modeling is robust Global Journal of Engineering and Technology Advances, 2025, 23(01), 347-362 362 [16] Miamo W. C., Saha J. C., Kakeu B. P., Kamdjo C. Achuo E. D. Analysis of the multiplier effects of basic public infrastructure on local entrepreneurship in cameroon. Journal of Developmental Entrepreneurship. 2024; Vol. 29, No. 02, 2450008. https://doi.org/10.1142/S1084946724500080 [17] Elime Bouboama A., Mamba Mpele, Ngouadjio A. C. Applying the life cycle analysis in the construction of social housing in cameroon: the case of single-storey houses at the sic residential Area in olembe (yaoundé). Sustainability in Environment. 2018; Vol. 3, No. 3, 207-229. https://core.ac.uk/download/pdf/268085796.pdf [18] Habibi A., Tavakoli H., Esmaeili A., Golzary A. Comparative life cycle assessment (LCA) of concrete mixtures: a critical review. European Journal of Environmental and Civil Engineering. 2022; Volume 27, 2023 - Issue 3 Pages 1285-1303. https://doi.org/10.1080/19648189.2022.2078885 [19] PRé Sustainability. SimaPro 9.5 Software Documentation. 2023; https://simapro.com [20] Habert, G., d’Espinose de Lacaillerie, J. B., Roussel, N. An environmental evaluation of geopolymer based concrete production: reviewing current research trends. Journal of Cleaner Production, 2011; 19(11), 1229-1238, https://doi.org/10.1016/j.jclepro.2011.03.012 [21] [21] Prusinski, J. R., Marceau M. L., Martha G. V. Life cycle inventory of slag cement concrete. Slag Cement Association / Portland Cement Association. 2007; PDF available via http://large.stanford.edu/courses/2016/ph240/pourshafeie2/docs/marceau-2007.pdf [22] De Schepper, M., Van den Heede, P., Van Driessche, I., De Belie, N. Life Cycle Assessment of Completely Recyclable Concrete. Materials. 2014; 7(8), 6010–6027. https://doi.org/10.3390/ma7086010 [23] INS Cameroon (Institut National de la Statistique). Annuaire statistique du Cameroun, Chapitre 4: Hanitat et conditions de vie, ECAM 4. 2019; Yaoundé: INS.https://ins-cameroun.cm/wpcontent/uploads/2021/02/0CHAPITRE-4_HABITAT-ET-CONDITIONS-DE-VIE.pdf [24] Rebitzer, G., Ekvall, T., Frischknecht, R., Hunkeler, D., Norris, G., Rydberg, T., Schmidt, W., Suh, S., Pennington, D. W. Life cycle assessment: Part 1: Framework, goal and scope definition, inventory analysis, and applications. Environment International. 2004; 30(5), 701–720. https://doi.org/10.1016/j.envint.2003.11.005 [25] Mbohwa C., Moyo S. Life cycle assessment of the cement industry in Zimbabwe. 15th CIRP International Conference on Life Cycle Engineering. 2008 ; https://hdl.handle.net/10210/14425 [26] Petek A., Masanet E., Horvath A., Stadel A. Life-cycle inventory analysis of concrete production: A critical review, Cement and Concrete Composites. 2014; Volume 51, Pages 38-48. https://doi.org/10.1016/j.cemconcomp.2014.03.005 [27] Petek Gursel, A. Life-Cycle Assessment of Concrete: Decision-Support Tool and Case Study Application (Doctoral dissertation, University of California, Berkeley, Department of Civil and Environmental Engineering). 2014; retrieved fromhttps://escholarship.org/content/qt5q24d64s/qt5q24d64s_noSplash_cfb277e51a7c50310b77aa1772e1b ecd.pdf [28] Jolliet O., Margni M., Charles R., Humbert S., Payet J., Rebitzer G., Rosenbaum R.. IMPACT 2002+: a new life cycle assessment methodology. Int J Life Cycle Assess. 2003; 8:324-330 DOI: 10.1007/BF02978505 [29] Baidai Y. D. A. Analyse de cycle de vie appliquée à un système de production d'eau potable: cas de l'unité industrielle SODECI nord-riviera. Master II Genie de l'Environnement, Institut de Formation à la Haute Expertise et de Recherché, France. 2011; Retrieve on https://www.memoireonline.com/a/fr/cart/show [30] Serres, N., Braymand, S., & Feugeas, F. Environmental evaluation of concrete made from recycled concrete aggregate implementing Life Cycle Assessment. Journal of Building Engineering. 2016; 5, 24–33. https://doi.org/10.1016/j.jobe.2015.11.004 [31] Brauer M., Amann M., Burnett R, T., Cohen A., Dentener F., Ezzati M., Henderson S. B., Krzyzanowski M., Martin R. V., Van Dingenen R., van Donkelaar A., Thurston G. D. Exposure assessment for estimation of the global burden of disease attributable to outdoor air pollution. On behalf of the Outdoor Air Pollution Expert Working Group of the Global Burden of Disease Project. Environ Sci Technol. 2012; 17; 46(2): 652–660. doi: 10.1021/es2025752.