Performance of local sands in mortar for cement quality control

Abstract

Standard sand plays a most important role in the cement industry. Not only is it used to asses the quality of cement but it is also required as a standard material to study the properties of other building materials e. g. lime, pozzolanas.In Kenya, the strength quality of produced cement is determined by the use of a standard sand imported from Britain. As a result of the exorbitant price of this imported sand. compliance tests and research on local cement and its associated products are significantly limited. In line with the prism method specified in International Standard ISO 679:89 and based on the findings of Mutua S.K.,this thesis study investigated the performance of selected local sands as a possible replacement for the imported standard sand. Mortar prisms, of varying mix parameters, were tested in flexure followed by compressive test on each of the broken halves of the prisms. Test results indicate that for the standard mix proportion and sand gradation specified in ISO 679:89, pi~ sands from three different sites in Msambweni and Tiwi produced 28-day mortar compressive strengths comparable (differing by less than 5%)to that of the imported European standard sand; a fourth pit sand from Msambweni produced reasonable 28-day compressive strength which was 91% of that of the European standard sand.It can thus be concluded that the four pit sands have a great potential for use as ISO or CEN standard sands. and could further be regraded• to produce sui table high yield Kenyan standard sand It is recommended that standard certification tests be conducted on the sands from Msambweni and Tiwi, with a view to establishing an equivalent national standard sand.