DEVELOPMENT OF NORMAL STRENGTH AND HIGH STRENGTH SELF CURING CONCRETE USING SUPER ABSORBING POLYMERS (SAP) AND COMPARISON OF STRENGTH CHARACTERISTICS

Abstract

As water is becoming a scarce material day-by-day, there is an urgent need to do research work pertaining to saving of water in making concrete and in constructions. Curing of concrete is maintaining satisfactory moisture content in concrete during its early stages in order to develop the desired properties. However, good curing is not always practical in many cases. Curing of concrete plays a major role in developing the concrete microstructure and pore structure and hence improves its durability and performance. Keeping importance to this, an attempt has been made to develop self curing concrete by using Super Absorbing Polymers as self curing agents. Compressive strength of concrete containing self curing agents is investigated and compared with conventionally cured concrete. Self curing agent increases the water retention capacity of the concrete by reducing evaporation of water from concrete. In this investigation, workability and strength characteristics of Normal Strength and High Strength Concrete, cast with the self curing agents have been studied and compared with the corresponding conventionally cured concrete. For the Normal Strength Self Curing Concrete of grade M20, M30 and M40, IS method of mix design was adopted. Mix proportions of High Strength Self Curing concrete of grade M60, M70 and M80 were obtained based on the guidelines given in modified ACI 211 method suggested by P.C.AITCIN. Super plasticizer dosage was varied with grade of concrete. Trial dosages of 0.8%, 1% and 1.2% of the weight of cement were used for M60, M70 and M80 grades of concrete respectively. Two self curing agents have been tried, out of which one has been found to be very effective. Trial dosage of 0.25% and 0.3% of the weight of cement was used for normal strength concrete and trial dosage of 0.4% of the weight of cement was used for High Strength Concrete. From the workability test results, it was found that the self curing agent has improved workability. It is found that concrete with this self curing agent gives more strength than that of the conventionally cured concrete. Also the percentage saving in cost of water has been found out and hence Self Curing Concrete holds economical.