Laboratory Investigation and Field Performance Evaluation for Chemically Stabilized Cement Treated Sub-Bases

Abstract

India is making significant investments in the transportation sector, but in many locations, the procurement and the processing cost of naturally available materials is exorbitantly increasing because of rapid depletion of these materials. In this work, soil that is readily available in the area, cement and nano-chemicals like Terracil and Zycobond are utilised to assess the impact of nano materials on California bearing ratio and compressive strength of chemically treated sub-base layer. XRD, SEM tests were carried out to identify the micro structure of different mixes. The addition of optimum dosage of nanoparticles had a very advantageous effect on UCS and CBR. The compressive strength of the soil aggregate mix treated with cement was improved by up to 103.4% by the addition of nano compounds. The California bearing ratio of the mix treated with optimum dosage of cement and chemical was increased by 219%. The different laboratory prepared mix were laid on the field (Intermediate lane, PMGSY road) to study a behaviour of mix. To examine the deflection and modulus for various mixes laid on the field, a deflectometric investigation employing a lightweight deflectometer was conducted. LWD was also used to calculate the 28-day modulus. SEM, XRD analysis depicted that the nanoparticles promoted the pozzolanic reaction by transforming portlandite into C-S-H gel. According to the X-ray diffraction patterns, stabilisation by terrasil and zycobond results in the creation of additional peaks like CSH and changes the structure of pure soil when gypsum is added. SEM pictures of soil samples reveal a denser texture as a result of chemical stabilisation and a decline in the Si/Al ratio, which suggests increased shear strength in stabilised samples according to interpretation of energy dispersive X-rays (EDS).