Determination of Setting Times of Mortar Mixtures Prepared with Cement Having Different C3A Ratios

Abstract

The duration of concrete transportation to the construction site, its workability and formworkremoval time are significantly affected by the setting time of cement. Therefore, it is of great importance toknow the initial and final setting times of concrete mixtures in construction applications. According to theliterature survey, the setting time of cementitious systems is generally determined on cement paste mixture bythe Vicat test. However, it was understood that a limited number of studies were carried out on thedetermination of the setting time using concrete mixtures. In this study, the effect of cement C3A ratio variationon the initial and final setting times of cementitious systems was determined using mortar mixtures. For thispurpose, mortar mixtures were prepared by using cement having four different C3A content (2%, 3%, 6% and9%). The ratios of water/cement and sand/cement as well as slump-flow values were kept constant as 0.485,2.75 and 27±2 cm, respectively. In order to provide the desired flowability, polycarboxylate ether-based waterreducing admixture (PCE) was used. The initial and final setting times of the mortar mixtures were determinedusing a concrete penetrometer equipment. According to the results, PCE demand to provide the target slumpflow value increased by increasing the cement C3A content. In addition, the setting time values reduction wasobserved with the increase of cement C3A content. It was determined that the results obtained are compatiblewith the literature.