The impact of burnt sawdust ash from timber species as partial cement replacements on the durability properties for sustainable interlocking blocks

Abstract

This study investigates the potential of Burnt Sawdust Ash (BSDA) from seven timber species (Wawa, Mansonia, Teak, Odum, Ceiba, Essah and Mahogany) as a partial cement replacement in laterite interlocking blocks (LIBs). Using a replacement level of 0–30 (BSDA) wt% and mix proportion of 1:6 (cement + BSDA: laterite) with a 0.60 water-to-cement ratio, 396 blocks or specimens of size 185 mm × 220 mm × 120 mm were produced and cured at normal temperature and humidity under shady and sunny conditions for 7, 14, 21 and 28 days as per the BS EN 771‑1:2011 + A1:2015. Soil characterization test, particle size distribution, bulk density, water absorption, and erosion resistance were tested. It was observed that, the lateritic soil that passed through 2.36 mm and the fineness of BSDA partially helped in better interlocking and strength gains.While replacing cement with BSDA generally increased erosion rates, wood type influenced both properties, with 10% of Wawa, Mansonia and Odum offering better water absorption and erosion resistance at higher sawdust compositions. A positive finding was the decrease in bulk density with increasing BSDA, making blocks lighter and easier to transport. The research findings have some impacts on environmental sustainability, speed construction, and construction cost reduction.