Compaction characteristics of lateritic soils stabilised with cement-calcined clay blends

Investigations on the potentials of pozzolans - silicate and aluminate materials - in civil engineering works is on the rise. Calcined kaolinite clay (CKC) is one of such pozzolans that has been regarded as an option for mitigating the release of greenhouse gases from cement. While investigations on its use with cement in concrete works is widespread, there is a gap in literature about its impact as a soil stabiliser for flexible road pavements. This work studies the compaction behaviour of two lateritic soils stabilised with a blend of Portland cement (PC) and CKC combined in CKC : PC ratios of 0:1, 1:3, 1:1, 3:1 and 1:0 with total binder percentages of 0 (control), 2.5, 5, 7.5 and 10 of the weight of soils. CKC was obtained by calcining clay samples sourced from south-west Nigeria at 700 degrees C for 1 hour. Two lateritic soils samples were adopted and classified as A-1-a and A-2-6 based on AASHTO system. Corresponding fineness modulus were 2.18 and 4.33 with cation exchange capacities (CEC s) of 1.678 meq/100 gms and 1.738 meq/100 gms respectively. The results show that, as the CKC:PC mixes varies, compaction behaviour of the stabilised A-2-6 soil was widely varied whereas it was minimally varied for the stabilised A-1-a soil. The differences in the particle sizes (fineness modulus) and CEC are adduced as factors responsible for these differences in compaction behaviour. However, the CEC s of the soils is about the same. Thus, the differences in compaction performance could only be attributed to differences in the particles sizes of the soils. Statistical evaluation of differences in the results using ANOV A confirms that the differences for the A-2-6 soil are significant whereas that of the A-1-a soil are not.