Research On Improving The Performance Of Ductile Iron Pipe Lined With Cement Mortar

Common ductile iron pipe lined with cement mortar will delaminate whencentrifugal molding process, which leads to the mortar delamination after steam curingand poor sticky, flaws, low intensity and other defects. Then those defects will influencethe quality and durability of the mortar. Meanwhile, at the beginning of using them,the water PH is higher than the tap PH standard.Taking economic and effective ways to improve the performance of mortar can notonly raise the quality of the tap water, but also can extend the life of mortar. Moreover,it will increase the decay resistance of cast tube. On the condition of the curing andcentrifugal, the optimized mortar have an better intensity and manufacturability andadaptability of curing.The results of the test turn out to be: the volume of mixed mineral powder can over50%when the water reducer and activator is appropriate or in the process of steamcuring. The test gives us the best proportions of the intensity compound gelled materialare:50%cement,40%mineral powder,4%plaster,7%ground limestone,0.7%superplasticizer and amidogen,0.25%pure soda,0.025%tributyl phosphate,0.02%sodium hexametaphosphate. This kind of material has wonderful sodiumhexametaphosphate and processing property. The test gives us the best proportions ofthe compound gelled material which can control the soda dissolving out are:40%cement,50%mineral powder,4%plaster,7%ground limestone,0.7%superplasticizerand amidogen,0.025%tributyl phosphate,0.02%sodium hexametaphosphate. Thiskind of compound mortar equip good sodium hexametaphosphate and processingproperty. It breaking strength raised from7.2MPa to11.2MPa, about44%. The28d compression strength of the mortar test block raised from50.7MPa to61.4MPa. Thesematerials have strong resistance of the decay of sulfate, which can replacesulfate-resistance cement or bauxite cement as lining to transport liquid withcorrodibility.The PH of first soaked water of sample small-bore tube decreased from12.48tobelow10. After3times continuous soak, the PH of the water reached below8.5. Whenmanufacturing big or medium-bore tube, the drawing intensity of the cement liner raisedfrom3.5MPa to the required≥5MPa. The mortar has fine liquidity, and the materialspread equally. And once it was molded, the surface is quite smooth so the times ofpolish is reduced.