Effects of burnt sawdust ashes from timber species on the strength properties of laterite-interlocking blocks

The most basic problem facing man is shelter, apart from food. This problem is acute in Ghana and other developing countries due mainly to the high growth rate of the population, inflation, unemployment and poor economic resources. Today in Ghana both middle and low income earners can hardly afford their own houses. From one point of view one can see that some of the materials used in building are of good quality and can last. The study aimed to partially replace ordinary Portland cement (oPc) with burnt sawdust ash (BSDA) from different timber species (Wawa, Mansonia, Teak, Odum, Ceiba, Essah and Mahogany) in making interlocking laterite blocks by replacing 0–30 wt %. Mix proportion was 1:8 (cement + BSDA: laterite) with a 0.60 water-to-cement ratio. 528 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. Compressive and tensile strengths were subsequently evaluated. However, an initial strength increase was observed with curing time for specific wood species (Wawa, Mansonia, Teak, Odum, Essah, Ceiba, and Mahogany). Notably,Wawa, Mansonia and Odum ash exhibited superior strength performance at 10–20% replacement levels, potentially satisfying relevant standards for load-bearing wall construction. This research suggests that up to 10% replacement with Wawa, Mansonia or Odum BSDA presents a promising eco-friendly approach for partially substituting oPc in LIB production.