PFA CONCRETE - NEAR-SURFACE ABSORPTION PROPERTIES

Water absorption properties of concrete made with ordinary (OPC) and rapid-hardening Portland cement (RHPC), and both cements blended with pulverized fuel ash (PFA), were studied for a design strength range of 25-70 N/mm2 at ages of 28 and 180 days, and with a number of curing conditions of varying relative humidity and temperature. It was found that with standard curing in water at 23-degrees-C, PFA enhanced the quality of concrete as judged by absorption properties. RHPC/PFA blends performed better than OPC alone, but blends with OPC gave better results than RHPC. Air curing greatly increased absorption, but this was no worse for PFA concrete than OPC or RHPC concrete. PFA concrete responded better than OPC concrete to curing temperature. The optimum PFA content varied with concrete type, curing regime and age.