A Comparative Study: Blended Cements Containing Analcime and Clinoptilolite

Abstract

The demand to blended cements is increasingly widespread due to clean environment and energy saving. In the future, this demand will not be met by currently additives on the market. For this reason, alternative additives will always be needed. The aim of this study is to provide a contribution for additive variety used in sustainable blended cement productions. Therefore, in this study, natural zeolite type clinoptilolite (C) which is widely used in blended cement production and different natural zeolite type analcime (A) are compared. These zeolites are natural pozzolans with volcanic tuff origin. Firstly, pozzolanic activities, mineralogical structures, physical and chemical properties of zeolites were determined. And then, the heat of hydration, setting times and compressive strength tests were performed on samples prepared by using Portland cement (PC) and natural zeolite blended cements. The replacement ratios of zeolites used in test samples are 0, 10, 30 and 50% of Portland cement weight. According to results of pozzolanic activity tests, the compressive strengths of lime-zeolite (pozzolan) mixtures were determined as 6.30MPa for analcime and 9.02MPa for clinoptilolite. The heats of hydration of blended cements containing analcime were lower than that of blended cements containing clinoptiloite and that of Portland cement at all replacement ratios. The setting times of blended cements containing analcime were determined as shorter than that of blended cements containing clinoptiloite and that of Portland cement. The compressive strengths of mortars containing analcime blended cements were slightly higher than that of mortars containing clinoptilolite blended cements. The optimum strength values of mortars containing both zeolite blended cements were obtained at 10% replacement ratio. According to the results obtained from the study, analcime exhibits similar properties to clinoptilolite. In some cases, due to these similar properties, analcime may be an alternative additive to clinoptilolite which is widely used in blended cement industry.