ASTM C1585-20 PDF Download

ASTM C1585-20 is a standard test method used to determine the rate of absorption of water by hydraulic-cement concretes. The purpose of this test is to assess the penetrability of the pore system in concrete, which is an important factor in determining its performance in aggressive environments. The test method is based on the concept of "water sorptivity" developed by Hall, where the rate of water ingress is mainly controlled by capillary rise due to absorption.

The water absorption of a concrete surface is influenced by various factors such as concrete mixture proportions, the presence of admixtures and cementitious materials, composition and physical characteristics of the cementitious component and aggregates, entrained air content, curing methods, hydration age, presence of microcracks, surface treatments, and placement techniques. The moisture condition of the concrete at the time of testing also affects water absorption.

This test method is designed to determine the susceptibility of unsaturated concrete to water penetration. It is important to note that the rate of absorption may differ between the concrete surface and the interior. The exterior surface, which is often exposed to less curing and more adverse conditions, may have a different absorption rate compared to the interior. The test allows for the evaluation of absorption at different depths by drilling a core and cutting it transversely.

It is worth mentioning that ASTM C1585-20 differs from Test Method C642, where specimens are oven-dried, immersed in water, and boiled. In ASTM C1585-20, only one surface of the specimen is exposed to water while the other surfaces are sealed to simulate water absorption in a member in contact with water on one side only. On the other hand, Test Method C642 estimates the maximum water absorption of a dry specimen, providing a measure of the total permeable pore space.