The effects of the early carbonation curing on the mechanical and porosity properties of high initial strength Portland cement pastes

摘要

Mechanical and porosity related properties of high initial strength sulfate resistant Portland cement (HS SR PC) pastes subjected to early age carbonation curing were investigated. This work presents the characterization through mechanical properties, of carbonated HS SR PC pastes and of non-carbonated references. They were treated at two different times of carbonation (1 h and 24 h), at the best conditions of capturing, previously determined by the authors. The mechanical properties were characterized by compressive strength, tensile strength by diametrical compression, elastic modulus and Poisson's coefficient. It was found that 1 h of carbonation improved the mechanical properties, while the increase of carbonation time to 24 h, decreased significantly the same properties in relation to the reference specimens. The porosity related properties were characterized by total absorption, absorption by capillarity, gas permeability, and mercury intrusion porosity. It was noticed that the increase of the carbonation time from 1 h to 24 h, increased substantially the absorption properties. Despite the mechanical properties of the 1 h carbonated paste were better than those of the reference, the absorbed water content of the carbonated specimen was slightly higher than that of the reference.