Global perspective on application of controlled low-strength material (CLSM) for trench backfilling - An overview

•Recent research developments and applications of CLSM for trench backfilling are overviewed.•CLSM specifications, practical applications and materials used by different countries are discussed.•Long-term site experiences and technical limitations of using CLSM are highlighted.•CLSM could be a beneficial way for recycling waste materials and industrial by-products.

Controlled low-strength material (CLSM) is known as a self-leveling and self-compacting cementitious backfill material used for backfilling. The aim of this paper is to give an overview of the research development and practical application of CLSM for trench backfilling. Widespread application of CLSM is found around the world including in the United States of America (USA) as well as in other developed and developing countries. The main specifications and guidelines used in the USA and referenced by most of the other countries are highlighted in this paper. In addition, long-term site performance and technical limitations to be considered before application of CLSM are also discussed. Based on 115 globally sourced literature articles, it is suggested that the materials used for the production of CLSM are varied from country to country which in turn could have a significant influence on the resulting properties and its application in the field. It is also demonstrated that use of high volume by-products or/and waste materials is an effective way to control the low strength requirement of CLSM and minimize the environmental concerns related to the disposal of these waste materials.