STABILISATION OF NIGER DELTA FAT CLAY WITH BLEND OF BINDERS FOR SUBGRADE APPLICATION (PART 3) - TRIAL STABILISED ROAD SECTIONS IN SAMPOU, NIGER DELTA

F. M. Alayaki; A. Al-Tabbaa; M. J. Ayotamuno

F. M. Alayaki Civil Engineering Department, Federal University of Agriculture Abeokuta, Nigeria
A. Al-Tabbaa Engineering Department, University of Cambridge, United Kingdom
M. J. Ayotamuno Faculty of Engineering, Rivers State University of Science and Technology, Nigeria

Keywords: Fat clay, Subgrade, Stabilisation, Trial road, Performance

Abstract

The field performance of subgrade fat clay stabilised with additives and cement (PC) was evaluate by constructing trial sections along Odoni-Agbere road in Sampou, Bayelsa state. The blends mixed with the subgrade used in the study were, Drill Cuttings Ash (DCA)-PC (1:1), sand-PC (4:1), and lateralite-PC (2:1). Comparison of the dry density of cored stabilised samples with the laboratory samples showed that 100% compaction was achieved in the field for all the sections. Dynamic Cone Penetrometer (DCP) and field plate loading tests were used to determine the in-situ California Bearing Ratio (CBR) and settlement respectively. The in-situ CBR of the unstabilised and stabilised sections exceeded the targeted 15%. However, the in-situ CBR of the unstabilised section could be compromised if the soil is excessively manipulated and excess water is present. The percentage increase in settlement after two cyclic loading operations for the stabilised section ranging from -17 to 7%. This study revealed that the stability of the stabilised sections could be ensured if they are sealed on or before the 45th day after construction.