Effects of carbon nanotube dosage and aggregate size distribution on mechanical property and microstructure of cemented rockfill

The mechanical and structural properties of cemented rockfill produced by mineral wastes as recycled aggregates limit its application. In this paper, the macroscopic mechanical and microscopic scanning tests were carried out to study the mechanical property and microstructure of cemented rockfill reinforced by carbon nanotubes (CNTs) and fractal aggregates. The strengthening and deterioration mechanisms of CNT dosage on cemented rockfill were revealed for systematically evaluating its engineering availability. The influencing mechanism of aggregate size distribution on cemented rockfill was clarified to analyze the contribution of optimizing aggregate size distribution. The results show that the strengthening of cemented rockfill by appropriate CNTs includes bridging microcracks, compacting micropores and reinforcing cemented matrix, while the deterioration by excessive CNTs is attributed to form the agglomerative clusters and hollow cemented matrices. The cemented rockfill with superior aggregate size distribution has uniform and dense microstructure with relatively few defects, which is conducive to CNT reinforcement.