Material Constants for Voids/Cement Ratio – Uniaxial Compressive Strength Relationship for Sands of Different Gradations

Abstract

The combination of Soil steadiness with cement has become an effective geotechnical engineering mechanism to improve the soil, especially in embankments, construction of subgrades for roads and railway lines where the mechanical properties of the supporting soils have a vital influence in strength and implementation of other mechanisms are increase in cost and extensive too. The selection of appropriate cement volume and energy compaction energy to produce a soil-cement mix is the key to achieve the target strength and stiffness at an optimum cost. Fonseca et al. presented a unique relationship using the voids/cement ratio stated by the absolute volume of voids separated by the absolute volume of cement (V_v/V_ce) and unconfined compression strength (q_u), which renders this selection possible. The V_v/V_ce - q_u relationship is a function of the type of soil and cement used for the study. This work's motto is to establish the impact of soil types and its grain size distribution on the material constants of this relationship. An extensive unconfined compression testing program was used in this study with poorly graded coarse sand. Three cement ratios, 5%, 10% and 12% were used to simulate the sand cementation. The amount of cement was based on dry unit weight of sand for different Cement contents. Since the Specific gravity of Portland pozzolona cement is greater than Palar sand, the dry density increased with the rise in cement content. The densities for 5% cement content is 1.51 g/cm³, 10% cement content is 1.55 g/cm³ and 12% cement content is 1.57 g/cm³. The specimens were cured in a chamber at 90% relative humidity with a temperature of 23°c ± 1° c. for 7 days, 14 days, and 28 days. To understand the influence of grain size distribution on the voids/cement ratio and unconfined compressive strength, many liberated compression strength and voids/cement ratio data for sand-cement admixtures with a different gradation of sands from the literature were analyzed and compared with the present study. This work aims to provide a good insight into the relationship between these indices and the V_v/V_ce - q_u correlations parameters. The material constants in the voids/cement ratio and uniaxial compressive strength relationship for sands of different gradations are evaluated, and their variation with the grain size distribution is established.