Methods for calcium carbonate content measurement of biocemented soils

Recently, a new soil improvement method to use a microbially induced calcium carbonate precipitation (MICP) process to generate biocementation in sand has been developed. In this method, the properties of biocemented soil are controlled by the calcium carbonate content produced through the MICP process. Various methods have been used in the literature to determine the calcium carbonate content in soil. However, the calcium carbonate content determination can be affected by the methods used and this effect has not been studied so far. In this paper, six different methods that can be adopted to measure the calcium carbonate content are examined experimentally: the titration, inductively coupled plasma (ICP), X-ray diffraction (XRD) TOPAS, thermogravimetric analysis (TGA), ASTM, and washing methods. The titration and ICP methods give the lowest value and the washing method the highest value. The other three methods, XRD TOPAS, TGA, and ASTM, produce values in between and the differences among the values measured by those three methods are small.