Strength properties of vacuum-dewatered concrete

Abstract

Experimental program is set up to study the effect of the vacuum dewatering process that accerates the rate of strength gain of concrete mixes, having the water-cement ratio and cement content as variables. The effect of the process on the mechanical properties of vacuum-dewatered concrete is also determined in comparison with those of the conventionally non-treated mix, including compressive strength, splitting tensile strength, modulus of rupture and secant modulus of elasticity. Only the mix with the cement content of 250 to 350 kg./cu.m. of concrete and the initial water-cement ratios of 0.48 to 0.62 are considered. The test results show that the rate of strength gain of the vacuum dewatered concrete is faster than that of the non-treated concrete. The compressive strength at 1-day, 3-day and 7-day age of the vacuum-dewatered concrete are in the same order of those ones of the non-treated concrete at 3-day, 7-day and 28-day age respectively. At 28-day age, the compressive strength of the vacuum-dewatered concrete is greater by about 13.37. for the mix with initial water-cement ratio of 0.48 to 51.77. for the mix with initial water-cement ratio of 0.62, respectively. The effect of cement content is in the same order of 15.57. to 63.7% for the mix with the cement content of 250 to 350 kg./cu.m. of concrete respectively. The other properties, as related to the ultimate compressive strength, are markedly increased.