IMPACT OF SUGARCANE MOLASSES IN CONCRETE AS TIME RETARDING AND WATER REDUCING ADMIXTURE
Creators: name: ASTER TAYE SERTE
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2019
Subjects: Sugarcane Molasses, Admixture, Retarder, Setting time, Workability

description: Concrete is one of the necessary materials in construction industry, because of its superior characteristics such as strength and durability. However, in certain situations Concrete is used in places because of setting time and workability problems. Retarding and water reducing admixtures are used in the concrete composition to improve the setting time, the workability and strength of the concrete. However; in Ethiopia the retarding and water reducing admixtures are expensive to import by foreign currency. Sugarcane molasses, a locally sourced admixture is another substitute that has been established to be a retarder and water reducer admixture in this study. Therefore the objective of this research is focused on the impact of sugarcane molasses in concrete as time retarding and a water reducing admixture. The Sugarcane molasses was collected from Metehara Sugar Factory. The following experiments were performed at room temperature in order to attain the objectives of this study which includes; Standard consistency test of cement paste with 0.2%, 0.4%, 0.6%, 0.8%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10% of molasses by weight of cement and 0% as a control, setting time test of cement paste by using 0.2%, 0.4%, 0.6%, 0.8%, 1%, 2%, 3%, 4%, 5% ,6% by weight of cement and 0% as a control, Slump test, compressive strength test and split tensile test of concrete by using 0%, 0.2%, 0.3%, 0.4%, and 0.6% of sugarcane molasses by weight of cement. For this research three types of concrete grade C25, C30 and C40 were executed properly. The total samples of 180 concrete cubes of size 150mm× 150mm × 150mm and cylinder of size 300mm×150mm were produced. From these samples 90 cubes were used for compressive strength test and 90 cylinders used for split tensile strengths test at 7 and 28 days curing periods for both. The above results had showed that Sugarcane molasses acted as accelerating admixture up to 0.4% dosage of molasses, and above 0.4% as a retarding admixture. This implies it acted as setting time accelerating admixture at lower dosage level and as setting time retarder admixture at higher dosage level. Sugarcane molasses were act as water reducing admixture and its capacity of reducing water were 3% reduction from 0.2% up to 6 % dosage level and by 8% reduction at 8% of dosage level of sugarcane molasses. The slump test value of the three concrete grades C25, C30 and C40 were increased due to the dosage level increment of sugarcane molasses. These imply that it improves the workability and water reducing capacity of concrete. After 28 days curing periods, the compressive strength and tensile strength of concrete were increased up to 0.4% dosage of molasses and at higher percentage of molasses, the strength were reduced. The 7 days curing period’s tensile strength was decrease with an increased percentage of molasses except 0.3% of dosage of molasses. These results revealed that 0.3% addition of sugar cane molasses gave the best results in compressive and tensile strengths tests of the concrete specimens made with concrete grade C25,C30 and C40 Therefore 0.3% proved to be optimum dosage. The possible output will reduce construction cost, develop wastage management system, improve concrete performance and reduced foreign currency by using locally available material. This study also needs further research on sugar cane molasses composition of different Sugar factories.<br>