ABSTRACT
Maximum and minimum void ratios are two parameters that have effect on mechanical behavior of soil. There are different parameters that have effect on value of void ratio such as size, angularity, roundness and shape of particles. Particles size and roundness were studied at this work. Angular calcareous sand was selected and tested at this study. For doing tests, soil was washed, dried and sieved at 6 different size groups from 0.3mm to 4.75mmm. The sieves dimensions were 0.30, 1.18, 1.40, 2.36, 2.80, 3.35 and 4.75mm. Minimum and maximum void ratios were founded at all of these 6 size groups. At the second step angular soil has been changed to rounded calcareous soil by placing and turning soil in Los-Angeles machine without balls for 50000 revolutions and after rewashing and sieving the soil, minimum and maximum void ratios calculated for these rounded calcareous samples too. Same procedure was repeated for preparing well-rounded soil and same tests were done on new samples. Results showed that minimum and maximum void ratio decreased by increasing the size of soil samples. Same behavior of decreasing void ratio was seen when roundness of particle increased. Another result that can be mentioned was that, bigger uniformity coefficient (Cu) and wider range of particle sizes caused smaller void ratio. Results cleared that on minimum void ratio, size of particles showed more effect on angular soil than well-rounded. For maximum void ratio, effect of particles size was more considerable at rounded and well-rounded soil.
