Burnt Sawdust Ash from Timber Species  as Partial Cement Replacements on the durability properties for Sustainable Interlocking Blocks

This study investigates the potential of wood ash (BSDA) from seven timber species 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 specimens of size 185 mm x 220 mm x 120 mm were produced and cured 7, 14, 21, and 28 days. Soil characterization test, particle size distribution, bulk density, water absorption, and erosion resistance were tested. While replacing cement with BSDA generally increased erosion rates, Wawa and Mahogany ashes exhibited superior resistance across all replacement levels. Wood type influenced both properties, with Odum, Ceiba and Mansonia offering better erosion resistance and desirable water absorption 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.