Number of Aggregate Sizes and Aggregate Gradation Area: A Correlational Study

Blending aggregates is a procedure of mixing the accessible aggregates for blending to meet the gradation specifications and achieve maximum density. The maximum density of the mix is estimated by considering several aggregate sizes and aggregate gradation areas. Here the research was carried out to find the optimum number of aggregate sizes that are to be adopted in the mix followed by considering the economic factor, it is known that if the no. of aggregate sizes is increased the gradation area decreases and vice versa, due to the presence of more aggregate’s size voids can be easily filled. But if there are a greater number of aggregate sizes are adopted the mechanized cost increases so the economy also should be in view while choosing the optimum number of aggregate sizes. An optimum number of aggregate sizes is estimated by evaluating how many aggregate sizes influence the gradation area of the mix. To study the influence of two variables on each other sample data containing combined gradation percentage passing along with sieve size and no. of aggregates used in the mix was collected. Later, graphs were developed for each mix to evaluate the gradation area by integrating the limits. A correlation was conducted between aggregate sizes in the mix and obtained gradation area. Similarly, Regression analysis is performed. The outcome of the correlation relation is a weak negative correlation with a value of −0.1486. Through regression analysis, linear equations are developed for the same and the P-Value of sample data is obtained to be 0.318754. Through this correlation and regression analysis, it is concluded that generated model can’t be accepted globally based on P-value. In order to make the model to be accepted globally more influence parameters must be added to the model in evaluating the gradation area, which can improve model performance.