Assessment of Fraction Effects on Flow Characteristic of Cement Mortar Using Natural and Manufactured Sand

The concrete’s workability is divided into three phases namely coarse aggregate phase, mortar phase and cement paste phase. The coarse aggregate phase comprises of coarse aggregate and mortar phase. The mortar phase of concrete primarily comprises of binder, fine aggregate and water. The function of mortar phase is to impart workability to the concrete. Holistically, factors like water content, shape of aggregates and gradation of aggregates plays an important role in regulating the workability of mortar. However, there is no such methodology established from which one can predict the workability of concrete based on the texture and shape parameters of aggregates. To study the relation of above-mentioned factors on the workability, tests were carried out using uniformly graded and well graded Natural sand and Manufactured sand for assessment of shape parameters and workability. The shape parameters of fine aggregates were obtained through Digital Image Processing (DIP) method which was conducted on at least 600 individual particles from each grade of both samples. The workability of cement mortar for both the samples are tested at water-cement ratios (0.3, 0.35, 0.40, 0.45, 0.5) and cement-sand ratios (1:1, 1:2, 1:3, 1:4). Mini flow table test was used to check workability in terms of its average flow. From the experimental results a relationship is developed, which states that the average flow of zone sand is proportional to the weighted average of the product of the average flow of the mortar for a particular sieve class, at its corresponding W/C and C/S ratio, and proportion in the given sand sample. The proposed equation to predict the workability of cement mortar is validated using test results.