STRENGTH CHARACTERISTICS OF REGROUND CAKED CEMENT

Abstract

The construction climate in Nigeria is fraught with so many problems that lead to projects not being executed as scheduled or eventual abandonment of site. These lead to the storage of purchased cement for times longer than necessary, resulting in their getting caked. Compounding this problem is the activities of some cement traders who re-bag cement after long periods of exposure and the importation of cement, which may have lost their properties due to long period of shipment.

Various tests were conducted on normal and reground-caked ordinary Portland cement (Elephant brand) with a view to determining the effect of long period of storage. The tests included mineralogical composition, consistence, fineness, soundness, setting times and strength performance of mortar and concrete cubes at different ages.

The results of the investigation showed a reduction in the Tricalcium Silicate (CS) as well as increase in Dicalcium Silicate (C₂S) contents of the reground-caked cement thus resulting in low strength capacity. The various strengths of mortar and concrete cubes cast with the reground-caked cement were about 10-28% those of the corresponding normal cement. The reground-caked cement is therefore recommended for use in non-load bearing elements and sandcrete blocks for partitions.