Soil-Based Flowable Fill for Pipeline Construction

This research investigated the performance of a soil-based flowable fill as an alternative backfill for pipeline construction. The excavated natural silty sand from a trench was used as the major ingredient in the flowable fill. The study consisted of two phases. In phase I, laboratory experiments were conducted to develop optimum mix formula. Tests included physical properties, flowability, and strength. In phase II, field trial construction was conducted to verify the accuracy of laboratory results and evaluate the field performance of the material. Based on the research, for strength values ranging from 300 to 1,000 kPa, the cement-to-water and water-to-solid ratios were the two most important parameters controlling the engineering performance of the material. Laboratory and field observations provided strong evidence that the use of soil-based flowable fill can be a practical solution and promote optimum quality for pipeline construction.