The Effect of Capping Condition on the Compressive Strength of Concrete Hollow Blocks

One of the quality control tests done on the concrete hollow blocks is the compressive strength. In order to simulate in situ strength of the concrete blocks, capping technique was used in order to achieve smooth perpendicular surface for compressive strength test specimens. Cement Capping is one of the most widely used methods in testing compressive strength of concrete hollow blocks. In this research, other types of capping was used in addition to cement-gyps capping that is wood capping by using of plywood plates on the compressive strength specimens. Specimens without any treatment for capping were also tested for comparative analysis. Cases of capping (or no capping) were considered for several types of hollow blocks (variable thickness) of 70,100,150 and 200 mm thickness. The results showed that no significant effect of the specimens size on the ratio of compressive strength between no-capping and cement-gyps capping, no-capping and plywood capping, and cement-gyps and plywood capping. The ratio of compressive strength between the cement-gyps and no-capping are approximately equal to the ratio between plywood and no-capping. The correlation established for compressive strength for Cement-gyps capping, and plywood capping was recommended for use interchangeably. Keywords: concert hollow blocks, compressive strength, capping type, cement-gyps capping, plywood capping.