The Cement Content Measurement of Cement Mixing Piles with EDTA Titration Method

The uniformity of cement mixing piles is visually tested on the drilled core samples, significantly relying on experience and extremely inaccurate. The cement content of core samples is an important parameter to quantify the uniformity of cement mixing piles. However, there were no well-accepted methods of testing the cement content of core samples. EDTA titration method is widely used as an effective way to test the cement content of cement-stabilized soil in highway subgrade. However, the cement mixing piles cannot be drilled until 28 days after construction, which causes remarkable change of water content and cement hydration during this period. In addition, factors affecting the EDTA titration results should be investigated before standard EDTA titration curves are constructed. In this paper, effects of different factors including curing method, curing period, soil type, content of water glass, and cement type, on EDTA titration testing results were investigated. It is found that cement type and soil type will significantly affect the test result. It is critical to keep the curing environment and soil unsieved before testing. Water glass will reduce the EDTA solution consumptions at early stages of curing. The EDTA titration results are verified by the proposed density estimation method.