The Effect of Alkaline Additives on the Operating Conditions of Kaolinitic Polymerization


​Jordanian kaolinite polymerization has been studied to determine the effect of using different alkaline materials such as NaOH, KOH, and Ca(OH)2, and sand as a filler on the compressive strength, durability under wet and dry conditions, and water absorption of the produced specimens. The studied parameters were mixing proportions such as; alkaline materials to kaolinite ratios, filler to kaolinite ratios, water to kaolinite ratios, and filler particles size. The polymerization step was carried out by mixing the kaolinitie and the filler with the alkaline solution in the case of NaOH and KOH before molding the specimens. In the case of Ca(OH)2, the kaolinitie, fillers, and powder of Ca(OH)2 were dry mixed together before water is added. The moulding step was carried out using a stainless steel mould at a pressure of about 15 MPa, the curing temperature was 80°C. Twenty four hours was the curing time for specimens containing NaOH or KOH, while 7 days was the curing time for Ca(OH)2 specimens. The obtained results indicate that using NaOH as an alkaline material has the best compressive strength of 45.45 MPa under dry condition, 20.38 MPa under wet condition, and the lowest water absorption of 9.41 %. The composition of the specimens with optimum values consist of 42.37 % kaolinite, 5.93 % NaOH, 42.37 % sand, and 9.32 % water, with sand particles size of (180-355) μm. The specimens of NaOH and sand as a filler showed highest durability under dry cycling condition compared with KOH specimens. While the specimens of KOH and sand as a filler showed highest durability under immersion, and wet cycling condition. © 2011 Jordan Journal of Mechanical and Industrial Engineering.