Characterization of pervious concrete exposed to high levels of evaporation

When fresh concrete is exposed to high levels of water by evaporation in structures with large ratios of surface/thickness these are prone to be altered in their constituent material properties, generating a decreased or poorer performance than they were conceived. The study shows the effects of high evaporation levels of exposure on pervious concretes, plain and reinforced with polymeric fibers exposed to extreme drying. By the continuous monitoring of the measured parameters, it is possible to establish the material behavior from the initial stage up to a stable behavior. Measurements of evaporation, vertical and horizontal strain and temperature served as parameters to support the theoretical framework of the behavior of the material by drying. The results of evaporation rates resulted very low if compared with non-pervious concretes and seem to be related with the corresponded strain values. Vertical and horizontal strains resulted similar between concretes and with very low values, where cracking was inhibited. The fiber addition resulted without any benefit in the strain reduction. An important factor found in the relationship between water loss and paste binder is the risk that w/b ratios arrive to critical values, where there is the possibility the minimum hydration kinetics cannot be completed, observed particularly in lower w/b concretes.