The geotechnical properties of soils differ from area to area, depending on the origin of soil, environmental conditions of a region, and soil treatment processes. As a subgrade material in pavement construction, however, the soil is required to meet specific standards for its engineering properties, such as plasticity, deformability, strength, and durability parameters. For this purpose, soil undergoes a stabilization process, in which it is treated with chemical additives. This paper studies the potential of limestone powder as a stabilizer in combination with cement in the stabilization of sulfate-contained saline soil. For this purpose, silty sand (A-2-4(0) according to AASHTO soil classification system) containing high sulfate and sodium contents was stabilized with 6% and 8% cement by dry weight, 2% and 4% limestone powder at fixed 4% cement content, and 2% limestone powder by dry weight at 6% cement content. Series of tests were performed to determine the improvement of geotechnical properties of these mixtures, such as unconfined compressive strength, Atterberg limits, three-dimensional (3-D) swelling, and dielectric constant. Experimental results show that the addition of limestone powder to the cement-treated saline soil decreases soil plasticity, increases maximum dry density, improves strength parameter, reduces volumetric swelling and moisture susceptibily of soil.

To decrease greenhouse gas emissions and maintain sustainable economic growth, the cement industry has developed limestone calcined clay cement (LC3). Many researchers have started to investigate the performance of LC3 as a construction material. However, the strength development of LC3 has diverging or opposite views. In this research, the strength development characteristics of ordinary Portland cement (OPC) and LC3 with different combinations of medium reactive ground granulated blast furnace slag (GGBFS) have been compared using compressive strength and ultrasonic pulse velocity, and maturity tests. The test result shows that the LC3 concrete has a similar 28-day compressive strength to OPC concrete despite developing a lower early age. Ultrasonic pulse velocity test results have matched compressive strength test results. The predicted compressive strengths using 7-day maturity data were comparable to actual strength results.

Road construction on sulfate-bearing soils is a worldwide concern because it is associated with a volume swelling stability issue due to the ettringite formation. Several treatment techniques were developed to solve this problem and improve geotechnical soil properties, including using pozzolanic materials and applying the mellowing process. This research evaluated the combined effect of cement and waste glass powder (WGP) on stabilizing sulfate-bearing soil before and after the mellowing procedure. Total six mixtures were developed, which includes 4% cement, 4% cement + 2% WGP, and 4% cement + 6% WGP before and after soil mellowing. The experimental program included particle size distribution of soil and stabilizers, chemical analyses of stabilizers, soil properties, unconfined compressive strength, and three-dimensional (3-D) swelling for the high sulfate-bearing kaolin clay. The test results demonstrated that the use of WGP in soil with a high sulfate content WGP improved strength development, decreased volumetric swelling, and reduced moisture susceptibility.