Effect of Cement Grinding on Workability of Concrete

摘要

In this paper, effect of grinding of portland cement on its consistency and workability of resulting concrete is investigated. Research work has been conducted over five cement factories and their average trend is discussed. Fresh clinker was collected from same batch of each factory. It was ground with 4% gypsum in a 13 kg ball mill. During the course of grinding, fineness was periodically measured using Blaines air permeability apparatus and from each factory, six cement samples, having fineness range from about 1500 cm~2/g to 4000 c~m2/g were prepared. In order to confirm uniform oxide ratio, their chemical composition was analyzed by XRF-Cement Spectroscopy. Consistency test of all the samples were performed in the laboratory. In order to have an idea of workability, slump test and compacting factor tests were performed on concrete mixes made consecutively by all samples keeping constant mix and water cement ratios. Graphs were drawn between fineness of cement and these properties, for each factory separately and comparative study of different trends found, were carried out. An average trend of the four factories was also drawn for each property under discussion. Relations between fineness of cement and workability of concrete were established by using Least Square Regression Method.