Effects of LC3 on the compaction and consistency properties of clay soils

Department of Civil Engineering, Faculty of Engineering, Bursa Uludag University, Nilüfer-Bursa, Türkiye

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Abstract

In the geotechnical field, ordinary Portland cement (PC) is frequently used as a chemical soil stabilization material. Considering the energy spent in the production of PC and the excess CO2 produced, it is vital to reduce cement consumption to increase sustainability. Researchers are investigating the use of alternative materials with lower CO2 emissions and production costs compared to PC. One of the alternative materials is limestone calcined clay cement (LC3). This cement type contains 53% PC, 2% gypsum, 15% limestone powder (CaCO₃), and 30% metakaolin. The novelty of this research lies in the comparative evaluation of standard LC3 and LC3 modified with Nano-CaCO3 to enhance the geotechnical properties of clayey soils. In this study, besides PC mixtures, different LC3 mixtures were obtained by replacing CaCO3 with Nano-CaCO3. These stabilizer mixtures were mixed with the clay soil sample at 5%, 10%, and 15% ratios. In order to investigate the soil stabilization effects, untreated soil and these 9 mixtures were subjected to Proctor tests after determining the Atterberg limits. Compared to the unstabilized soil, the maximum dry density (MDD) values increased by 4.24% with the addition of 15% PC. Similarly, the MDD values increased 2.32% with 15% LC3 mixture. Furthermore, 2.31% increment was observed with the addition of 15% LC3 containing Nano-CaCO3 (LC3-NC). Moreover, the Atterberg test results indicate that, increasing the dosage of stabilizer decreased the liquid limit (LL) and plastic index (PI) values of the soil and increased the plastic limits (PL) for all mixtures.