Projects Correlating CBR and EV2 Strength Gain across Six Irish Soil Stabilisation

This paper demonstrates how data from trial test areas on six Irish sites has led to increased confidence in achieving soil stabilisation specifications within an economic and sustainable framework. Soil stabilisation typically involves undertaking field trials to verify the soil-binder mix design and to confirm the construction methodology. Quality assurance on the sites included plate load testing (PLT). These tests were performed at various time intervals to generate time-strength curves and indicative stiffness properties for the stabilised soil via CBR and EV2 parameters, derived from the PLTs. The design strength and stiffness properties used are typically the 28-day values. However, waiting 28-days for each stabilised lift to acquire the desired properties is not practical and often leads to the binder content being increased to achieve the required strength within 24 hours. In this paper, the CBR and EV2 growth trends from the combined six trial areas are presented along with suggested criteria for the control of soil stabilisation works. The results show there is potential for the binder content to be reduced while still achieving typical project specifications thus leading to a more sustainable ground improvement technique.