Improvement of the bearing capacity of lateritic gravel by a geopolymer binder: road construction in tropical countries

Owing to its availability and affordability, lateritic soils are one of common building materials widely used for the development of infrastructures in sub-tropical and tropical regions. Their engineering properties are mostly influenced by such factors including climate, vegetation, typography, and parent rock. Seeking a proper method to improve the bearing ability of lateritic soils is still of interest. The present work deals with the use of low-energy and alternative pozzolan based-geopolymer binder for the lateritic gravel’s stabilization for road construction in tropical countries. The stabilization ratio of 0 up 15 wt% were made and labelled LS0, LS5, LS10 and LS15, respectively. The synthesized products were characterized using several analytical techniques including mineralogical, geotechnical, and physical characteristics. The results revealed the efficiency of geopolymer binders to improve the load-bearing capacity of gravelly soils. Optimal characteristics are obtained with the samples made with 10 wt% of the geopolymer binder (IP ≤ 20, CBR > 164.2 and density between 1.8 and 2). This allowed us to classify LS5 as a foundation layer material for T₁–T₃ traffic, LS10 and LS15 for the base layer of T₁–T₃ traffic and a foundation layer above T₃. The use of the natural pozzolan based geopolymer, subject to a durability study, appears as an eco-efficient way for the stabilization of lateritic gravel for road construction in tropical nations in the same way as hydraulic binders.