Strength Characteristics of Laterized Concrete Using Lime – Volcanic Ash Cement

Abstract

The effect of calcium oxide on volcanic ash laterized concrete was investigated. A total of 60 cubes of 150mm dimensions were cast with volcanic ash (V.A) and calcium oxide (CaO) combination of 90%:10% and 80%:20% respectively while the ordinary Portland cement (OPC) based concrete for 28-day target strength of 25N/mm2 served as control. Sand replacement by laterite also varied between 0% and 20% for the laterized specimens. The cubes were cured in water and tested for compressive strength at 7, 14, 21, and 28 days. The result showed that the compressive strength increased as the hydration period increased and that the presence of calcium oxide boosted the strength properties of volcanic ash laterized concrete. The compressive strength of the laterized concrete specimens was higher at the various hydration days for the 20%lat/20%CaO: 80%V.A. sample than the 10%lat/10%CaO: 90%V.A sample. The 28-day strength for 20%lat/20%CaO: 80%V.A sample gave a value of 22.07N/mm2 (i.e. 81.74%) as against the 21.53N/mm2 (79.74%) gotten for the 10%lat/10%CaO: 90%V.A. sample, while the control mix gave a 28-day strength value of 27.0N/mm2 (100%). The volcanic ash – lime cement in the laterized concrete specimens, therefore, reflects good pozzolanic activity and can be adopted for the construction of buildings and rural infrastructure