Dynamic carbonation curing of fresh lightweight concrete

Abstract

The reaction of fresh lightweight concrete with carbon dioxide during early-age carbonation curing is hindered by surface saturation due to vibration consolidation. To promote a high degree of carbonation of fresh lightweight concretes, a dynamic carbonation system was developed to remove surface free water and inject carbon dioxide simultaneously. Based on cement mass, the resulting carbon uptake reached 13% in 4 h carbonation and 20% in 18 h carbonation. The early strength by fresh carbonation is comparable to that of steam curing, while the late strength is higher in a much reduced process time. The dynamic system can effectively control the relative humidity of the chamber to prevent water accumulation and create a route of capillaries for carbon dioxide diffusion and precipitation of carbonates. Dynamic carbonation creates a carbonate–bond matrix. The process provides an excellent means to recycle carbon dioxide, with economic and environmental benefits.