Influence of hardened cement paste content on the water absorption of fine recycled concrete aggregates

摘要

A linear relationship was found between the mean size of four granular classes(0/0.63, 0.63/1.25, 1.25/2.5, 2.5/5 mm) of different laboratory-made fine recycledconcrete aggregates (FRCA) and their hardened cement paste content (CPC).A method based on salicylic acid dissolution was specifically developed for themeasurement of CPC. Results showed that bound water and density of FRCA werestrongly correlated with their CPC. Identically, the water absorption coefficient alsofollowed a linear trend as a function of the CPC but only for the three coarsergranular classes. Indeed, the water absorption coefficient of the finer fraction ofFRCA (0/0.63 mm) cannot be correctly measured using European standard methodEN 1097-6 or method no. 78 of IFSTTAR; but it can be obtained by extrapolationfrom the previous linear trend. As a consequence, the accurate total water absorptionof FRCA (fraction 0/5 mm) can be estimated.