Influence of Cement Type and Curing and Conditions on Initial Absorption of Concrete

Abstract

This paper deals with the measurement of concrete durability by means of an initial absorption test of the concrete surface. The criterion used for this analysis is the amount of water absorbed after one hour. The specimens were placed in a constant water level of 1 cm, and the quantity of absorbed water was measured by mass. The influence of cement type, temperature, relative humidity and surface protection in the initial absorption was observed. Two concrete mixtures were made with ordinary portland cement blended with calcareous filler (12% and 25% by mass). These concretes were cured at two temperatures (20 degrees C and 40 degrees C) and different relative humidities (30%, 60% and 100%). In some specimens a curing compound was used to observe its influence on surface protection from initial water absorption. The concrete strengths ranged from 28 to 62 MPa. The esperimental results showed that by changing the relative humidity from 60% to 100% during 7 days, the initial absorption can diminish by a factor of 2. The curing temperature can increase the initial absorption by 64%. The curing compound has a real influence in the concrete initial absorption.