Strength Variation of OPC-Saw Dust Ash Composites with Percentage Saw Dust Ash

Abstract

This work investigated the variation of OPC-Saw Dust Ash (SDA) composites strength with percentage SDA. 231 concrete cubes, 231 sandcrete cubes, and 231 soilcrete cubes of 150mm x 150mm x 150mm were produced at percentage OPC replacement with SDA of 0% (control), 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50% and crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, and 90 days of curing. For concrete, the 90-day strength values decreased from 28.00N/mm² at 5% SDA to 25.60N/mm² at 15% SDA to 20.50N/mm² at 35% SDA to 15.80N/mm² at 50% SDA, while the control value was 27.00N/mm². The 90-day strength values also decreased from 11.50N/mm² at 5% SDA to 5.40N/mm² at 50% SDA for sandcrete while the control value was 11.10N/mm². Soilcrete strength values decreased from 9.70N/mm² at 5% SDA to 4.50N/mm² at 50% SDA while the control value was 9.50N/mm². The results suggest that, with good quality control of the concreting process, 5% to 25% OPC replacement with SDA could be suitable for general reinforced concrete works, 25% to 40% for minor works in concrete, and 45% to 50% for plain concrete works. Also, 5% to 20% OPC replacement with SDA could be used for light load-bearing sandcrete and soilcrete works, while 25% to 50% could still be suitable for non-load-bearing works.

Keywords: Blended cement, Composites, Compressive strength, Concrete, Sandcrete, Saw dust ash, Soilcrete.