Utilization of calcite and calcite-cement in the stabilization of laterites for low-cost hollow blocks

This paper examines the production of calcite and calcite-cement stabilized laterite hollow blocks as low-cost masonry units. First, is the production of laterite hollow blocks solely stabilized with finely ground limestone or calcite followed by the production of laterite hollow blocks stabilized with calcite-cement composite. Laterite was sourced from three locations: Asoro, Evbuotubu and Ugbowo. Blocks were produced using a specially constructed machine with percentages of calcite and calcite-cement content varing from 4% to 16% respectively at compactive pressures of 10.32 and 13.75N/mm(2). Equal amounts of calcite and cement are used in the composite. The blocks were then tested for 7, 14 and 28 days strengths after curing. The results show that laterite blocks stabilized with calcite alone do not satisfy the Nigerian Industrial Standards or British Standards for blocks but those stabilized with 8% calcite-cement content, i.e., 4% calcite with 4% cement do, at moulding pressure of 13.7 N/mm(2). Based on the local cost data, the results also show that calcite-cement stabilized laterite hollow blocks are 17% cheaper than an equivalent cement-stabilized hollow block and 46% cheaper than the low quality sandcrete blocks sold in the market.