Duco No.4 is a unique chloride free accelerating admixture which is ideal for increasing rate of strength gain and it offers the effect of slow temperature by accelerating the rate of setting,strength gain and heat evolution.work can be continued under adverse weather condition of the concrete and without fear of chloride corrosion for concrete and work made to fixed workability the plasticising action of DUCO No.4 enable a reduction in water cement ration.DUCO NO.4 gives increased rates of production due to the higher early strength of concrete.