Acceptance criteria for fill compaction works

Abstract

Compared to the acceptance criteria for earthworks in public works projects in other countries and districts as well as the acceptance criteria for compressive strength of concrete cubes, the current standard in HK, which allows no tolerance of the RC value less than 95% in most situations seems too stringent. And this standard puts all the risk on contractors in that they would be pressured to place excessive compaction effort to the fill body to fulfill the project specification, the contractors pay for the clients for the quality of the products they have received. To achieve a balance between the contractor’s risk and the client’s risk in the earthwork projects, this paper proposed an adaption to current standards by allowing a certain degree of tolerance in RC test results. 80 numbers of completed earthwork projects have been analyzed to trial the proposed adaptions, and the Operating Characteristic Curve and Monte Carlo Simulation are used to confirm the rationality and applicability of the enhancement. Based on the results of the study, the adaption of replacing individual RC test result with moving average of 3 consecutive RC test results over the 95% threshold is considered applicable.