The effect of sodium aluminate on the properties of the composite cements

Abstract

The effect of sodium aluminate activator on properties of the Portland-composite cement (clinker factor 65 %) was studied and the results are being discussed. It is shown that the introduction of sodium aluminate (Na[Al(OH)4]) leads to an increase in the water demand of cement and a decrease in its strength. The results showed that the sodium aluminate and polycarboxylate ether (PCE) admixtures ensure the production of higher strength cements. It has been found that the addition of Na[Al(OH)4] – PCE significantly increases the compressive strength of cement mortar, particularly at 10–48 h of hydration. XRD and SEM measurements confirm that the hydration of composite cement with the addition of Na[Al(OH)4] – PCE is greatly accelerated by the way of formation of intense lines ettringite. It has been shown that the introduction of a sodium aluminate into the cement mortars allows to accelerate hardening and increase early strength and using of composite cement will provide improved performance and suitability. The results have shown that alkaline accelerator and polycarboxylate were effective for decrease shrinkage of composite cements.