International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 08 | Aug 2025
p-ISSN: 2395-0072
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Utilization of Spent Coffee Grounds as Partial Replacement for Fine Aggregate in Concrete Ajay Kumar R PG Student (M tech), Department of Civil Engineering, Dr. Ambedkar Institute of Technology, Karnataka, India. ---------------------------------------------------------------------***--------------------------------------------------------------------assessments showed that a 5% substitution achieved the best Abstract - This study examines M25 concrete where natural
balance in mixes and composures, lowering thermal conductivity by far more than 70% while preserving acceptable good strength. Beyond this proportion of mixes, thermal conductivity benefits continued but strength dropped notably by further.
fine aggregate is partially substituted with spent coffee grounds (SCG) at 12%, 15%, and 18% by weight. Mechanical performance was evaluated via compressive, flexural, and split tensile strength at 7, 14, and 28 days. Outcomes indicate a small improvement at 12% and decreasing strengths at 15% and 18%. The approach valorizes SCG while conserving natural river sand and manufactured sand.
Lachheb et al. (2019) [4] This study explains and examined plaster material composites where fine aggregate sand was replaced by 2 and 6% by spent coffee grounds. Testing thermal conductivity and energy demand for the mix showed conductivity and decreased from 0.50 to 0.31 W/m·K at 6% in addition. This translated into a 20% reduction in heating and cooling loads, with minor compromise to structural behavior of the concrete.
Key Words: spent coffee grounds, fine aggregate replacement, M25 Concrete, compressive strength, flexural strength, split tensile, sustainable concrete.
1.INTRODUCTION Concrete production relies heavily on natural sand and manufactured sand, the extraction and manufacturing process of which challenges environmental sustainability. Simultaneously, global, and Local coffee consumption generates substantial spent coffee grounds (SCG). Incorporating SCG into concrete offers a dual benefit that is waste diversion into converting into useful raw material and natural resource conservation as it is a finite element.
1.2 RESEARCH GAP ANALYSIS Limited focus on structural-grade concrete: Most studies emphasize mortars, plasters, or laboratory-scale mixes, with scarce evaluation of SCG use in structural M25 or highergrade concrete. Narrow range of mechanical testing: Prior research often concentrates on compressive strength, while flexural and split tensile strengths are less explored in detail.
1.1 Literature Review Senol (2024) [1] This study explores mortars with cement partially substituted by incinerated coffee waste at 2.5%, 5%, and 7.5%. Workability and strength tests were conducted and evaluations revealed that 2.5% replacement preserved adequate satisfying performance, but higher percentages sharp suddenly reduced mechanical properties. The study highlighted careful and needful dosage control as essential to maintaining both durability and usability of all mixes.
Lack of optimization window: Though many report declines at higher percentages, few studies clearly establish the optimum substitution level for fine aggregate. Durability aspects underexplored: Long-term performance indicators such as sorptivity, chloride penetration, shrinkage, and microstructural effects have received minimal attention.
Almeida et al. (2023) [2] This study evaluates sand concrete with natural sand which is partially replaced by 5% of spent coffee grounds. Compressive strength testing demonstrated slight improvement due to finding denser particle packing and reduced voids in microstructure level. At this dosage of spent coffee grounds, the material retained its mechanical integrity and strength while reducing reliance on natural sand, offering both sustainability and efficiency benefits for industry and sustainability.
Sustainability assessment gap: Life-cycle analysis and economic feasibility of SCG substitution remain largely unquantified in existing literature. (Limited focus on structural concrete, less work on mechanical parameters, less exposure to durability parameters)
2. OBJECTIVE
Charai et al. (2022) [3] In this study investigated by replacing
To investigate the feasibility studies of utilizing spent coffee grounds (SCG) as a partial replacement for natural
cement with pyrolysed ash derived from spent coffee grounds in mortar. Thermal and mechanical performance
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