Effects of Hollow Sizes on the Properties of Sandcrete Blocks

Two-cell hollow sandcrete blocks constitute the dominant wall construction material for modern shelter in many African countries, especially Nigeria. The hollow cavities in the block have adverse effect on its mechanical characteristics. This study investigated the effects of hollow sizes on the properties of sandcrete blocks. Sandcrete blocks of size 225 × 225 × 450 mm with varying hollow sizes of 175 × 187.5, 173 ×190 and 180 × 210 mm and web thickness 25, 35 and 15 mm respectively; were produced using cement: sand ratio of 1:12. The blocks were tested for compressive strength, density and water absorption. The results indicated that compressive strength at 28 days for blocks with hollow sizes 175 × 187.5, 173 ×190 and 180 × 210 mm are 5.22, 3.64 and 0.41 Nmm-2 respectively. The corresponding densities are 2307.56, 2589.15 and 1715.23 kg/m³ while the rate of water absorption are 22.2, 18.8 and 24.5%, respectively. It was concluded that the larger the size of the hollow in sandcrete blocks the lower their mechanical properties.