Investigation of unconfined compressive strength of cement mixed sand compacted under various static pressures

In this study, the way how unconfined compression strength of cement added sand changes according to cement content, water/cement ratio, compression pressure and curing time was researched. In the study, sand passing from ASTM No.16 sieve and retaining on ASTM No.30 sieve was used as material. Pozzolanic cement was used as binding material. The sieve analysis, specific gravity and maximum and minimum dry density determination tests were performed on sand. Also, maximum and minimum dry density determination tests were carried out on cement ? sand mixtures which were prepared for unconfined compression tests. The unconfined compression strengths of the samples used under the scope of the study that were prepared by minimum and maximum static pressures (8MPa and 40 MPa) and that had 4 different cement / sand ratios (2,5%, 5%, 7,5%, 10%) were obtained after being cured for 7 days and 28 days. In order to study the effect of compression pressure on unconfined compression strength, samples prepared by 10% cement by weight and by 6 different static pressures (4, 8, 16, 24, 32 and 40 MPa) were cured for 7 and 28 days period and then were tested under unconfined compression tests. All cement/sand mixtures were prepared at 3 different water/cement ratios (1,0, 1,5 and 2,0) and as 3 identical samples. According to test results it was determined that as cement content of cement-sand mixture and compression pressure increased, the unconfined compression strength increased as well. On the other hand, it was observed that as water content of cement-sand mixture increased, the unconfined compression strength showed a decreasing trend. Due to the increase in curing time from 7 days to 28 days, 2 to 3 times increase occurred in the unconfined compression strength of almost all samples.