A model for predicting carbonation of high-volume fly ash concrete

The carbonation process and the factors affecting concrete carbonation are presented. A mathematical model based on carbonation process for predicting the carbonation depth of high-volume fly ash (HVFA) concrete was developed. An accelerated carbonation test was conducted on ordinary Portland cement (OPC) concrete and HVFA concrete. The depths of carbonation predicted from the model are compared with the test results. It is shown that the effective water/binder ratio and the cement content are the key factors affecting HVFA concrete carbonation. The increase of curing period can improve the carbonation behavior of HVFA concrete. The carbonation behavior of HVFA concrete with appropriate mix proportion can meet the requirements of structural concrete. The agreement between test results and the prediction from the model is good. The model can be used to predict the evolution of carbonation depth with time. (C) 2000 Elsevier Science Ltd. All rights reserved.