Investigation on the behaviour of Concrete using chemical additives

Infrastructure development across the world created demand for construction materials. Concrete is the premier civil engineering construction material. Concrete manufacturing involve consumption of ingredients like cement, aggregates, water and admixture(s). The problems of concreting in cold weather arises from the action of frost on fresh concrete. When wet concrete freezes, the water in the concrete transforms into ice and thus increases the overall volume of concrete. Since there is now no water available for hydration of cement, setting and hardening of concrete are delayed. This damages the concrete to such an extent that it is unfit for use. An accelerating additive is used to accelerate the rate of hydration (setting) and strength development of concrete at an early age. This paper investigates the behaviour of concrete using accelerating additive. Experimental program is set up to compare 3 day, 7 days and 28 day compressive strength, flexural strength and tensile strength of commixtured concrete with plain concrete. This paper also focuses on the assessment of the role of accelerating additive in helping the rate of gain of early strength and the harmful effects of the accelerator on concrete properties. The optimum percentage of accelerator that could be used without harming the properties of concrete is also arrived at.