Research on the carbonation resistance of concretes containing dolomite powder

Abstract

This study focused on the carbonation resistance of concretes incorporating dolomite powder with water–binder ratio (w/b) of 0.55 and 0.36. The micro-morphology, micro-pore structure and carbonation depth of cement-based materials incorporating dolomite powder were investigated by scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and carbonization test box. The 28-day carbonation depth of concretes with a w/b of 0.55 in the case of dolomite powder at 50 wt% replacement level decreased by 39.62% compared with that of pure concretes. The carbonation resistance of concretes was improved with increasing dolomite powder dosage due to the fact that dolomite powder had the pore refinement efficiency on the carbonated cement pastes. The service life of concretes with a w/b of 0.55 incorporating dolomite powder under natural carbonation condition was obtained based on Alekseyev’s carbonation correction model. The durability life of concrete structure with a w/b of 0.55 was prolonged with the addition of dolomite powder. After carbonation for 28 days, concretes with a w/b of 0.36 were hardly affected by carbonation corrosion. The pore structure of concretes with a w/b of 0.36 became dense, inhibiting the penetration of CO₂ into the concretes due to a lower water–binder ratio.

Keywords:

• Dolomite powder
• carbonation resistance
• pore structure
• carbonation depth
• life prediction model

Additional information

Funding

The authors acknowledge the financial support for the National Key Research and Development Program of China (Project No. 2019YFC1906203).