Characterization of a shotcrete mix design with Microfibrillated Cellulose and Cellulose Ether -An investigation of physical, mechanical, rheological and chemical properties

Abstract

Shotcrete is a type of concrete, applied by spraying the concrete mixture at high velocities on a surface. Shotcrete is often used for tunnelling and mining operations. As the cement industry is a significant contributor to greenhouse gas emissions, there is a growing focus on incorporating environmentally friendly additives to make the industry more sustainable. Microfibrillated cellulose (MFC) and Cellulose ether (CE) are two environmentally friendly additives, mainly made from cellulose. These additives demonstrate great potential to be implemented in shotcrete mixtures, due to their properties such as high water retention and shear-thinning behaviour. Incorporating MFC and CE into a shotcrete mixture offer potential for improving the performance while simultaneously reducing the carbon footprint.This study conducts a characterization of a shotcrete mixture design with various MFC and CE dosages. Laboratory tests are performed to determine its physical, mechanical, rheological and chemical properties. The results show that MFC and CE functions effectively as viscosity modifying admixtures (VMAs) while preserving satisfactory workability. The workability, sprayability and pumpability should however be tested further with a field spray test. It was noticed an increase in compressive strength for both MFC and CE samples after 7 days of curing. The MFC and CE additives had a small deaccelerating effect on the overall setting time. This research emphasized the potential of MFC and CE to improve shotcrete performance, showcasing a solution to increase sustainability in the construction industry.