Publication Abstract

Proceedings of the Deep Mixing 2015 Conference, (DFI)

Stabilization Trials for Soft Soils in a High Sulfate Environment
G. A. Chapman, Golder Associates, Australia; A. Bouazza, Monash University, Australia; A. S. Russell, Golder Associates, Australia

This paper summarizes the results of a laboratory soil mixing trial carried out on soft clays as part of a site investigation for a proposed Liquefied Natural Gas (LNG) facility in Australia. The behaviour of soft clay samples mixed with varying concentrations of binder including agricultural lime (calcium carbonate), quicklime (calcium oxide), ordinary Portland cement and fly ash (blended 1:1 by mass) and quicklime-fly ash (blended 1:1 by mass) was assessed under a range of elevated sulphate conditions. The test results indicated that soil stabilized with 150 kg/m3 of fly ash/cement binder showed significant strength gain and did not develop any potentially expansive crystalline pozzolanic by products. The laboratory test program, whilst aimed as assessing the most appropriate stabilization binder, also addressed the short and long term performance of stabilized mixes in the presence of elevated concentrations of sulphate and chloride ions. Accelerated aging tests were carried out using high temperature water curing of samples to assess the effect of exposing cured samples to high levels of sulphates, and the short and long term volume change behaviour of samples. Testing included unconfined compressive strength tests on mixed samples, samples cured at elevated temperature whilst exposed to high levels of sulphates, oedometer tests on samples exposed to distilled and high sulphate concentration water, shrink swell tests, mortar bar extension tests and scanning electron microscopy and x-ray fluorescence tests.

 article #2083; publication #1013 (DM-2015)