Research On Holding Slump Grinding Aids To Improve The Compatibility Of Cement And Additive

It is certain for cement grinding aids to extensively use from the development trend of world cement industry. At present, there are numberless researches on cement grinding aids and production departments in China, but all of which were focus on grinding and increasing effect of grinding aids, improving grain composition, and flowing property, less research on the impaction of grinding aids on the compatibility of cement and chemistical additive, especially the compatibility of conceret surperplasticizer. So, the following aspects were studied in this paper.Firstly, 10 ordinary grinding aids monomer were systematically studied. The results show that, after grinding 14 minutes, the better grinding effects are trimeric sodium phosphate, triethanolamine, glycerin and diethylene glycol; after 30 minutes, sodium hexametahposphate, sodium stearate, triethanolamine, glycerin, diethylene glycol and ethanediol; after 14 and 30 minutes, triethanolamine, glycerin and diethylene glycol. More obvious grinding aids of the early enhanced effect are triethanolamine, trimeric sodium phosphate, and glycerin; the later age is glycerin. The compatibility of cement and naphthalene- or aminosulfonic-based superplasticizer could be improved by adding grinding aids sodium hexametahposphate or trimeric sodium phosphate. And the effects of these grinding aids on setting time, the water requirement of consistency for cement and soundness aren't very great. Also, the mechanism that grinding aids monomer affects the compatibility of cement and additive was studied.Secondly, two liquid and one solid composite holding slump grinding aids were developed using sodium hexametahposphate and trimeric sodium phosphate as main constituent. In the course of optimizing proportion, the clinker of three factories were respectively tested and gained prospective effect. The grinding effects of these grinding aids under various additions and grinding time were studied, and the influence of cement property under various additions was studied. The results show that each property of the three grinding aids is prior to that of grinding aids monomer; the compatibility of cement and additive has been improved, and the defects of traditional grinding aids, such as single property, bad compatibility, high cost and bad influence of cement property, could be overcome.Finally, from the above research, optimal addition of three composite holding slump grinding aids was determined. These grinding aids of optimal addition were tested by standard method, and their each property conforms with JC/T667-2004. This research provides the basis of further developing composite holding slump grinding aids and of extensively using grinding aids.