Coupling binder hydration, temperature and compressive strength development of underground cemented paste backfill at early ages

Cemented paste backfill (CPB) is an engineered mixture containing up to 60% solid tailings, and 3–7% binder (often) and water. CBP is used in backfilling underground mine voids. It receives great interest as one of the most commonly used ways in mine backfilling around the world. The usage of CPB greatly contributes to the disposal of mining tailings waste from the surface, increasing working place stability to extract more minerals safely. The key parameter for the design of CPB structure is its strength; namely, unconfined compressive strength (UCS). Knowing the time at which the CPB reaches its reasonable strength is very important for reducing the mining cycle and ensuring the safety of mine workers. As a cemented material, CPB strength is time and temperature dependent, and a function of the degree of hydration. The objective of this paper is to develop a numerical model for predicting the UCS of undrained CPB. Strength development is coupled with temperature and degree of hydration. For validation purposes, the predicted UCS will be compared with three groups of experimental results. The results show a good agreement between the predicted and measured values, and a new formula is suggested for including the effect of temperature into the UCS of CPB.