Laboratory Studies on Factors That Influence the Strength of Reinforced Cemented Sand

Abstract

This study was undertaken to investigate the effectiveness of Portland cement and wire mesh reinforcements in increasing the strength of poorly graded sands. To accomplish this broad objective, the selected sand was mixed with four levels of cement (2, 4, 6 and 8 percent) by dry weight of the soil and cured for 0, 14 and 28 days. Additionally, two types of wire meshes were used as reinforcements, namely, galvanized welded wire mesh and galvanized woven wire mesh. These were introduced at four levels of spacing 50, 35, 25 and 15 mm. For each combination of these variables two samples (100 mm × 100 mm × 200 mm in height) were prepared and tested in unconfined compression with the average strength value used in the analysis. Results indicated that the unconfined compressive strength of the cemented sand substantially increased with the percent cement and curing time approaching a maximum at 28 days curing. On the other hand, mesh reinforcements resulted in a further marked increase in the unconfined compressive strength especially when the spacing became less than 25 mm. Such an increase reached about 15 times the initial strength when the sample was mixed with 2 percent cement, cured for 28 days and reinforcements placed at 15 mm spacings. In general, mesh reinforcements allowed the specimens to absorb strains up to three times that of the cemented soil. Furthermore, the woven wire meshes were found to be superior to the welded wire meshes which produced greater strength and transformed the cemented sand into a relatively more ductile material.