Experimental Study on Physical and Mechanical Characteristics of Concrete with Partial Replacement of Cement by Wood ash and Partial Replacement of Fine Aggregate by Saw Dust Dowder

Abstract

Concrete is building material made by mixing cementing material and mineral aggregate with sufficient water to cause cement to set and bind entire mass. Now a days, due to demand of concrete increasing in construction work, it is necessary to develop such sources or material which can replace cement and sand in concrete. However, the cost of cement is rising due to high expenses of production and transportation. Finding alternative construction methods and material to reduce consumption of cement and sand could help reduce the concrete ingredients and their cost. This experimental study aims to investigate optimum replacement percentage and physical as well as mechanical properties of concrete obtained by patrial replacement of cement by wood ash and partial replacement of fine aggregate by saw dust powder. This process could potentially lead to development of sustainable alternatives to conventional concrete materials by utilizing industrial and agricultural by-products, thereby promoting light weight and eco-friendly construction practices. In this research, a total of thirty-six concrete cubes of sizes 15 cm×15cm×15cm and thirty-six number of rectangular concrete beams of sizes 10cm×10cm ×50 cm was tested to evaluate physical and mechanical properties including compressive strength, flexural strength, water absorption, workability of concrete and specific gravity, sieve analysis (gradation) and fineness test of concrete ingredients. The physical and mechanical properties of these mixes were compared with conventional concrete to assess performance. For the test, specimens were divided into four test schemes, (0%, 2.5%, 5% and 7.5%) replacements of cement by wooden ash and fine aggregate by saw dust powder respectively. Each scheme consisted of three specimens (for 7 days, 14 days and 28 days strength by average of 3 samples of each tests scheme). There were additional three concrete cubes for water absorption test and four slump cone samples for workability test were cast. The study concludes that compressive strength decreased with the addition of wood ash and sawdust powder from the beginning, while the flexure strength started to decrease beyond 5% replacement of wood ash and sawdust powder, which have properties of lower binding capacity and increase concrete porosity. So partial replacements of cement and fine aggregate by wood ash and saw dust powder respectively up to 5% can be effectively used in concrete, contributing to waste utilization, reduced environmental impact, and cost optimization.