THE USE OF WATER REDUCING ADMIXTURE TO REDUCE THE RISING OF DAMPNESS IN BUILDING

ABSTRACT The aim of this study is to determine the possibility of using Water Reducing Admixture with sole objective of reducing the Rising Dampness in Buildings. Two experiments were conducted on sandcrete blocks containing water reducing admixture with the aim of determining the compressive strength and water absorption. A total of 75 sandcrete blocks were produced, 45 numbers of the blocks were used for compressive strength test analysis and the remaining 30 numbers of the blocks were used for water absorption test analysis. compressive strength of sandcrete block containing the varying percentage of silicon chemical admixture; for 7 days of curing with 0% admixture is 5.8N /mm2, the one of 0.5% is 6.33N/mm2, the one of 1.0% is 6.8N/mm2, the one of 1.5% is 8.4N/mm2 and that of 2.0% admixture having compressive of 6.27N/mm2. The compressive strength of sandcrete block with 0% admixture for 14 days of curing is 6.0N /mm2, the one of 0.5% is 6.40N/mm2, the one of 1.0% is 7.7N/mm2, the one of 1.5% is 8.80N/mm2 and that of 2.0% admixture having compressive of 7.87N/mm2. The compressive strength of sandcrete block with 0% admixture for 28 days of curing is 6.2N /mm2, the one of 0.5% is 6.90N/mm2, the one of 1.0% is 7.90N/mm2, the one of 1.5% is 10.2N/mm2 and that of 2.0% admixture having compressive of 8.5N/mm2. The percentage of water absorption of a sandcrete block with varying percentage of silicon chemical admixture. For 24hrs of curing at 0% admixture is 5.3%, in 0.5% admixture the water absorption is 4.3%, in 1.0% the absorption of water 4.0%, in 1.5% the water absorption is 3.53% and in that of 2.0% admixture the water absorption is 3.22%. For 3 days of curing at 0% admixture is 6.8%, in 0.5% admixture the water absorption is 5.4%, in 1.0% the absorption of water 4.9%, in 1.5% the water absorption is 3.72% and in that of 2.0% admixture the water absorption is 2.61%. For 7 days of curing at 0% admixture is 7.5%, in 0.5% admixture the water absorption is 6.4%, in 1.0% the absorption of water 5.8%, in 1.5% the water absorption is 3.92% and in that of 2.0% admixture the water absorption is 1.64%. Water reducing admixture plays an important role in the production of high strength and durable sandcrete block considering the result of first and second experiments which are compressive strength test and water absorption test of the sandcrete block produced with the varying percentage of silicon chemical admixture showed that 1.5% of silicon admixture content added in cementenous materials produced a sandcrete block of higher compressive strength with the lower rate of water absorption. By going further, in the increase of silicon chemical admixture in to the mixture of sandcrete block mortar (i.e. 2% silicon content) yielded a less compressive strength, which means that the appropriate and suitable percentage of silicon content to be used should be 1.5%. The study recommends that, water reducing admixture is used in increasing the compressive strength of sandcrete block and it’s used in reducing the rising dampness in building to the bearest minimum.