Effect of Molasses on Properties of C-25 Concrete as Admixture

Abstract

Concrete is one of the most widely used construction materials. As the growth of construction industry increases, the demand and costs of construction material increases. In concrete technology, additional materials are needed to improve properties of concrete such as admixtures. The major advantage of admixtures in concrete is important to improveworkability, strength, and setting time, impermeability and colorof concrete. But, as we know in our country there is lack of admixtures and it is expensive to be used in construction. Hence, researcher is attempting to use the locally available waste materials (by product) as an effective and economical additive to maintain quality of concrete. This research therefore evaluated the Effect of Molasses on properties of C-25 Concrete as Admixture. The study was conducted by laboratory Experimental design in order to detect the effect of molasses on concrete properties.A concrete without molasses for control sample and seven trial with varying percent of molasses were taken and three cubes of 150mm x 150mm x 150 mm for compressive strength at 3, 7,14 and 28 days of curing age was casted. These percentages were 0.1%, 0.2%,0.3%,0.4%,0.5%,0.6% and,0.7% of molasses by weight of cement. The materials used were batched by weight and mixing was carried out with concrete mixing machine in the mix ratio of 1:2:2.56 with w/c ratio of 0.5. While the percentage of molasses was dissolved in mix water before adding to the mix of the concrete. As a result, it has been Noticed that the concrete production with the addition of successive percentage of molasses shows delay in the initial and final setting time and as the molasses dosage increase in the mix, the slump value also increased. Moreover, a concrete prepared with various percent of molasses shows a slight increase in compressive strength at later ages. The optimum value of compressive strength taken from concrete containing 0.1 up to 0.7% of molasses. Based on the test result,6.98%, 10.41% 13.54%,7.88%,3.86%, 2.43% and 1.03 % increase in compressive strength was observed for 0.1%,0.2%, 0.3%,0.4%, 0.5%, 0.6% and 0.7%, of molasses at 28-day curing age respectively when compared with the control sample. Therefore, the 0.3% of molasses was taken as optimum dosage of molasses. Finally, it is concluded that When the amount of molasses increases in the cement paste, the initial and final setting time of the paste is prolonged. The Compressive strength of concrete with molasses at early age is lower than the concrete with zero molasses. But, the compressive strength at later age i.e. at 28 days is higher than the Compressive strength of concrete group.It is recommended that, to use molasses as a water reducing and retarding admixture in replacing the chemical admixture wherever required.