Water permeability and chloride penetrability of high-strength lightweight aggregate concrete

This paper presents an experimental study on the water permeability and chloride penetrability of high-strength lightweight concrete (LWC) in comparison to that of high-strength normal-weight concrete (NWC) with or without silica fume. The results were also compared with those of the concrete at a normal-strength level of about 30-40 MPa. In order to compare the water permeability and chloride-ion penetrability, LWC and NWC had the same proportion by volume. The only difference between them was the coarse aggregate used. The results indicated that at the strength level of about 30-40 MPa, the water permeability of the LWC was lower than that of the corresponding NWC. However, the water permeability of the high-strength LWC and NWC was of the same order. The resistance of the LWC to the chloride penetration was similar to that of the corresponding NWC both in the normal-strength and high-strength levels. As the compressive strength of the LWC was lower than that of the corresponding NWC, the results indicated that for a given 28-day strength, the LWC would probably have high resistance to water and chloride-ion penetration than the NWC. The results indicated that the resistance to the chloride penetration does not seem to be correlated to the water permeability of the concrete. There appears to be, however, a direct relationship between the rapid chloride penetrability determined by ASTM C 1202 and the observed chloride penetration depth determined by the immersion and salt ponding tests. (C) 2002 Elsevier Science Ltd. All rights reserved.