Deicer-scaling resistance of phosphate cement-based binder for rapid repair of concrete

In this paper, a magnesium phosphate cement-based binder (MPB) was prepared by mixing MgO with mono-ammonium phosphate, borax and fly ash. The deicer-scaling resistance of MPB mortar and concrete and the bond strength loss between MPB paste and mortar with ordinary Portland cement (OPC) concrete were investigated. Experimental results show that MPB materials themselves have high deicer-frost resistance, which is not lower than that of OPC concrete with the air content of 4.5-6.5%. The bond strength loss between MPB materials and OPC concrete with the air-entraining agent is obviously lower than that between MPB and OPC concrete without the air-entraining agent, and the higher the air content in OPC concrete is, the smaller the loss is. Furthermore, the air-bubble parameters were analyzed, which indicate that MPB mortar and concrete can also obtain a reasonable air-bubble structure by chemical reactions. (C) 2002 Elsevier Science Ltd. All rights reserved.