High Absorptive Normal Weight Aggregates Used as Internal Curing Agents to Reduce Hot Weather Concreting and Curing Detrimental Effects

Abstract

The objective of this research was to quantify the effect of the mixing temperature, as well as curing conditions, on concrete mechanical and durability properties. Sixteen mixtures were cast and specimens were tested at various ages. The w/c ratio of the mixtures was kept constant, whereas the type of aggregates, casting and curing temperature varied. A concrete batch was designed using low absorptive Normal Weight Aggregates (NWA), whereas a second concrete batch included High Absorptive Normal Weight Aggregates (HANWA), at a saturated surface dried (SSD) condition. The HANWA were intended to deliver internal curing water (IC) to the mixtures in order to improve their performance. The mixtures constituent materials were conditioned at 22, 30, 35 and 40 degrees Celsius prior mixing. Two different types of curing regimes have been applied, aiming to evaluate the effect on specimens exposed to both hot environmental conditions and also day to night temperature fluctuations, as opposed on identical, water cured specimens. It was observed that the HANWA mixtures had improved mechanical and durability properties, a fact that was attributed to IC.