Experimental Investigation of Wheat Straw Ash and Eggshell Powder Composite as Partial Replacement of Cement in Concrete

Abstract

Concrete remains crucial for the construction industry and plays a vital role in a country's development by meeting infrastructure demands and enhancing capacity. Cement, as the primary component of concrete, is widely utilized worldwide. However, the adverse effects of cement production on natural resources, and environmental, and energy utilization have driven the construction industry's interest in supplementary cementitious materials. Therefore, substituting cement with supplementary materials offers an opportunity to reduce cement demand in the construction sector. Research objective is to investigate the potential use of a blending eggshell powder and wheat straw ash partially replacing cementitious material on mechanical and durability properties in C-25 Concrete with 5%, 10%, 15%, 20%, and 25% of OPC with eggshell and wheat straw ash composite of mix-1(0-0), mix-2(5-5), mix-3(5-10), mix 4(10-5), mix-5(10-10), mix-6(15-5) and mix-7(15-10) of eggshell powder-wheat straw ash respectively investigated. The chemical composition of eggshell powder and wheat straw ash was examined and the summation of major oxide (SiO2, Al2O3, and Fe2O3) is 86.97 %, for wheat straw ash and classified under class F pozzolanic materials and Concrete mix design as per ACI standard. The result also shows that the workability of concrete decreases as the eggshell powder and wheat straw ash replacement increases. From 28- and 56-day results Mix 1(Control) and Mix-6(15%ESP-5%WSA) attain the target mean compressive strength(33.5Mpa) of C-25 concrete according to the ACI standards. As per IS 456 2000 the flexural strength of concrete is computed and attains the requirement for flexural strength of 3.5Mpa for C-25 concrete except for mix-7, and blended concrete improved its resistance to sulphuric acid attack which proved the durability of concrete enhanced due to replacement. SEM results showed that the inclusion of WSA reduced the free lime content due to the pozzolanic reactions and displayed the formation of dense concert as the inclusion of supplementary material. XRD result also displayed Portlandite (CH) is decreased as the inclusion of supplementary material and also the formation of ettringite is hindered.