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 formwork removal time are significantly affected by the setting time of cement. Therefore, it is of great importance to know the initial and final setting times of concrete mixtures in construction applications. According to the literature survey, the setting time of cementitious systems is generally determined on cement paste mixture by the Vicat test. However, it was understood that a limited number of studies were carried out on the determination of the setting time using concrete mixtures. In this study, the effect of cement C3A ratio variation on the initial and final setting times of cementitious systems was determined using mortar mixtures. For this purpose, mortar mixtures were prepared by using cement having four different C3A content (2%, 3%, 6% and 9%). 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 determined using 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 was observed with the increase of cement C3A content. It was determined that the results obtained are compatible with the literature.

Keywords

• C3A
• Penetrometer
• PCE requirement
• Setting time