Suitability of Laterite Fines as a Partial Replacement for Sand in the Production of Sandcrete Bricks
The provision of affordable housing units from indigenous building materials has been the focus of most researchers in recent times. This paper focuses on the utilisation of laterite fines as replacement for sand in the production of sandcrete bricks as masonry units. With a mix ratio and a water/cement ratio of 1:6 and 0.50 respectively, batches with 0% (control specimens), 10%, 20%, 30%, 40% and 50% laterite fines replacing the sand were adopted in this study. In all, 96 bricks were cast, tested and compared with those of conventional sandcrete bricks (control specimens). Tests studied were density, compressive strengths (wet and dry) and water absorption. Data results revealed that the laterite fines used could satisfactorily replace the sand up to 30% for the production of structural masonry units even though bricks need to be protected when used in waterlogged areas or below ground level.
Effect of grain size on the strength characteristics of cement-stabilized lateritic soils
Abstract Lateritic soils are readily available all over Nigeria and as such have attracterd several research studies in recent times, the obvious aim being its utilization in the construction industry. This paper gives an account of the work done to further classify the usefulness and limitations of lateritic soils. Cement was used as the stabilizer and the lateritic soils used were obtained from the Ifewara deposits located about 10 km along Ife-Ifewara Road. A sieve analysis of the sample was made. Five different grain size ranges, from coarse to fine, were extracted from the samples. Cubes were moulded by mixing each grain size range with cement in five different proportions, the optimum water/cement ratio of each mix proportion being determined beforehand. The compressive strengths of the cubes were determined after 7, 21, and 28 days of curing in water, respectively. It was established that the higher the laterite/cement ratio, the lesser the compressive strength, and that the finer the grain size range, the higher the compressive strength. Finally, it was observed that cubes made using laterite/cement mix proportions 1:1 and 3:1 kept gaining strength with age while the others were losing strength.
Geoelectric reserve estimation of laterite deposits along a basement complex underlain Osogbo-Iwo Highway, Southwest Nigeria
Geoelectrical investigation, involving the Vertical Electrical Sounding (VES), was carried out at eight borrow pit sites within the corridor of the Osogbo - Iwo Highway with a view to estimating the reserve of laterite for the highway rehabilitation works. The area is underlain by a suite of basement rocks which vary from gneiss/migmatite to schist pegmatised, charnockite, meta-intrusives and fine-medium grained granite. The VES involved the Schlumberger array with half current-current electrode spacing varying from 1 to 65 m. The subsurface sequence beneath the proposed borrow pits is generally made up of four geologic layers comprising the topsoil (which is lateritic in places), laterite, weathered layer and the basement bedrock. The 1st and or the 2nd layer constitute(s) the lateritic layer with resistivity values generally greater than 300Ω-m and average thickness varying from 0.8 m to 13.3 m. The areal extent of the investigated sites ranges from 2,368 to 6,056 m2. The estimated volume of laterite deposit at the sites ranges from 3,816 m3 to 59,731m3. Out of the eight borrow pits investigated, only three (Pits 1, 2 and 6) are considered as viable for mining, from the point of view of the reserve while Pit 3 is considered marginally viable. The remaining four sites (Pits 4, 5, 7 and 8) have low reserve of laterite. The overburden thickness within the proposed borrow pits are generally thin, making open cast mining attractive. This study shows that lateritic soils required for road construction are more developed on schist and charnockitic rocks than on quartzites and granitic rocks.