Effect of peanut and sunflower shell ash on properties of sustainable high-strength concrete

Abstract

The aim of this study is to utilize agricultural waste ash as a partial replacement for cement to create sustainable high-strength concrete (SHSC). A maximum of 40 % of the cement mass was substituted with silica fume (SF), peanut shell ash (PSA), and sunflower shell ash (SSA). Tests were conducted on the fresh, hardened, and transport properties of SHSC, as well as on the microstructure, to evaluate the effectiveness of agricultural waste ash and the performance of SHSC. The slump test was used to assess the fresh characteristics of SHSC, while several tests were conducted to determine its mechanical properties, including splitting tensile strength, flexural strength, compressive strength (CS), and modulus elasticity. The SHSC's transport properties were evaluated through tests to determine their water permeability, chloride penetration, and water sorptivity. The results showed the possibility of producing concrete by replacing 40 % of the cement weight with SF, SSA, and PSA, achieving compressive strengths of 78.4, 66.3, and 57.4 MPa, respectively. The CS was 71.9, 67, and 61.5 MPa when the binary mixture (SF + SSA), (SF + PSA), and (SSA + PSA) were used as partial replacements for 40 % of cement weight, respectively, while the CS reference mixture was 72.6. MPa. The optimal replacement rate for cement is 30 % SSA or 10 % PSA by weight of cement to achieve acceptable mechanical and transport properties. The high replacement rate (up to 40 %) of cement weight resulted in a slight negative effect on the transport properties of SHSC compared to the control mixture.