Establishment of best practices for laboratory evaluation of stabilized base layers and comparative study on influence of different types of stabilizers

The stabilization of pavement layers is nowadays widely accepted across the globe due to several issues like scarcity of good quality aggregates, weak subgrade, presence of undesirable material, heavy loadings, and many more. The present study envisaged the suitability of different stabilizers available commercially for the stabilization of the base layer. The primary objective of the study is to ascertain the stabilizer which will aid in attaining the required strength with a minimum curing period while keeping the other characteristics of the stabilized mix under permissible limits. Three different types of cementitious stabilizers were incorporated in the study, namely polymer-based cementitious material (Commercial Chemical Stabilzer-1 or CCS-1), fiber-based cementitious material (CCS-2), and Ordinary Portland Cement (OPC) Grade-53. The microstructure analysis of the three stabilizers was also conducted to understand their mineralogical compositions. The desired level of compaction was achieved through the vibratory hammer approach after adopting different compaction methods during the laboratory study. The optimum content of stabilizers was determined by a trial-and-error approach, and the corresponding moisture-density relationship was utilized further for sample preparation. Moreover, several sets of samples were prepared, which were subjected to different curing periods. The samples were prepared in different shapes and sizes as required for conducting tests such as Unconfined Compressive Strength (UCS), flexural strength, Indirect Tensile Strength (ITS), and durability. For a detailed investigation of the stabilizer effect on the stabilized mix, the micro-structure analysis through X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) was performed. The laboratory study concluded that the minimum requisite UCS strength of 4.5 MPa was achieved by adding only 4% of CCS-1 in comparison to 4.5% of the other two stabilizers, i.e., CCS-2 and OPC-53. Moreover, the strength gains by stabilized mix prepared by the addition of CCS-1 are relatively fast, and the requisite strength was attained after 3-days curing only. The other test results also demonstrated the superiority of CCS-1 over the other two stabilizers. The microstructure analysis depicted that the formation of hydration products influencing the mix strength was relatively more for CCS-1.