An investigation on the use of coarse volcanic scoria as sand in Portland cement mortar

In this study, the utilization of coarse volcanic scoria CVS as sand in Portland cement mortar was investigated. The aim of this study is to give some physical properties, mechanical properties and durability properties of CVS mortars investigated at short term of curing in comparison with a reference mortar. Investigation was carried out on three groups of mortar samples according to the proportion of fine particles on the coarse volcanic scoria, “low” for the first group MCVS1, “average” for the second group MCVS2 and “high” for the third group MCVS3. The reference mortar has been made with standard sand. The water–cement w/c ratio and sand/cement s/c ratio used in the mixtures were 0.5 and 3, respectively according to European Standard EN 196-1-2005. The particle size of CVS aggregates used to prepare mortar mixtures were between 0.08 mm and 2.00 mm like in the standard sand. Compressive and flexural strengths were tested at mortar age of 28 days. The results revealed improved compressive and flexural strengths, which were maximal for the MCVS3 samples. Unit weight increased with the ratio of fine CVS size between 0.08–1.00 mm. Sorptivity and carbonation depth decrease as the ratio of fine CVS increase. Based on these results, using Cameroonian volcanic scoria in the appropriate particles size ratio composition will improve these mortar characteristics. CVS mortars can be used for more applications for building construction in Cameroon and all over the world, especially in regions where volcanic scoria resources are abundant.