Suitability of Flood Plain Deposits for the Production of Burnt Bricks in Parts of Benue State, Central Nigeria

In Benue State, Central Nigeria, flood plain soil deposits along the banks of major rivers and seasonal streams are used as raw materials in the local manufacture of burnt bricks for the construction of houses. This work evaluates the compositional characteristics of the soils and engineering properties of derived bricks to assess their suitability and as alternatives to sandcrete as load bearing materials in the construction of houses. The soils are composed of varying proportions of sand, silt and clay. While the sand fraction is mainly fine to medium grained, the clays are of low plasticity. The chemistry of the soils show that the order of abundance of the major oxides is CaO > Fe2O3 > MgO > TiO2 > PbO > MnO > Al2O3 > P2O5 > K2O >Na2O > SiO2 >AgO. Test cube bricks produced under standard compaction methods gave cold water absorption of 3-4%, ignition loss of 31-36 % and compressive strength of between 38 and 111N/mm2. These parameters satisfy the requirements specified by relevant Nigerian Standards for burnt bricks. The locally made bricks by the natives on examination exhibited cracks and shades of different colours due to thermal stress suggesting that low compactive efforts were applied during kneading of the soil into the molds and also that the bricks were not adequately fired. This quality deficiency is due to non -standardization of the hand production process. If properly harnessed, these widely available raw materials and their cheap products will readily substitute cement bricks for most housing and other structural work.