Seismic modulus growth of lime-stabilised soil during curing

Abstract

This paper presents a study conducted to characterise seismic modulus growth in lime-stabilised soil (LSS) throughout 28-day curing using free-free resonance testing. The motivation for this study is to explore the prediction of 28-day modulus and strength from seismic modulus data collected during early curing, and in general to investigate the efficacy of seismic testing as a method of quality assessment for LSS. Measured E and G growth ranged from 250% to 900% during curing for the three soils. Modulus values and growth in modulus were significantly influenced by mineralogy and soil processing. The growth in seismic modulus for each soil exhibited a power law relationship with curing time. The 28-day modulus was estimated within 8% error for two soils using early curing modulus data, that is, through 7 days. Seismic modulus was found to correlate linearly with unconfined compressive strength (qu) throughout curing. The proportionality of E and qu remained constant during curing for each soil beyond day 3. The study shows that early curing seismic data – that is, through 7, 8 or 9 days – is capable of providing a good estimate of 28-day E and qu if the variability is reasonable (here, range/mean < 0·5).