Experimental study on Sustainable reuse of the muck to produce two-component grout Backfilling

Tunnel Boring Machines are widely used for the construction of tunnel infrastructures. As a result, a considerable volume of muck is frequently generated during the excavation process. This muck can be considered an essential resource for other constructions and can be reused again. One of the aspects that generated muck can be reused for the aim of sustainability is backfill grouting, especially in two-component grout, which is a widespread technique with a lot of versatility and its fast reaction in order to avoid settlement. Two-component grout consists of component A, a mortar, and component B, an accelerator, which can be used in shielded TBM. Thus, a laboratory test campaign was performed to understand the effect of the presence of aggregate in a two-component grout. In this campaign, ten different mix designs were prepared with various amounts of aggregate. For each sample, different tests such as flowability, unit weight, bleeding on component A and gel time on the gelled grout, which is a mixture of components A and B, and finally, Surface Compressive Strength (SCS) and Uniaxial Compressive Strength (UCS) on the hardened grout were measured, and results were presented at the end.