Use of Carbonation Curing to Improve Mechanical Strength and Durability of Pervious Concrete

Carbonation curing is a promising method for CO₂ sequestration and strength improvement of cement-based materials. For normal cement concretes, the carbonation dominantly occurs in the outer layer zone of the specimen, and the overall strength improvement for a real structure is limited. Because of the high interconnected void content, pervious concrete is regarded as a better recipient for CO₂ curing. This paper aims to investigate the influence of carbonation curing on mechanical and durability performance of pervious concrete. Experimental results show that appropriate carbonation curing can effectively improve compressive strength, especially at early ages. Compared with conventional concrete, carbonation of pervious concrete is deeper and more homogeneous. However, pervious concrete becomes more sensitive to excessive carbonation so the carbonation duration needs to be strictly controlled. In addition, carbonation curing could significantly improve freeze-Thaw and leaching resistance of pervious concrete. Mercury intrusion porosimetry results show that carbonation curing can reduce the influence of leaching on critical pore diameter but can hardly prevent the increase of macropores content caused by freeze-Thaw. Analysis of BSE images shows that carbonation curing can improve the interfaces between aggregates and cement paste in pervious concrete and decrease the porosity of the interfacial transition zone. Therefore, carbonation curing is applicable for manufacturing long-Term durable pervious concrete products.