Leaching assessment of aerated concrete made of recycled shale gas drilling cuttings: Particular pollutants, physical performance and environmental characterization

Abstract

This research aims to study how feasible it is to apply water-based drilling cuttings (WDC), Phosphogypsum (PG) and fly-ash in a coordinated way in aerated concrete, while also adopting non-autoclaved technology which can greatly save energy consumption. So the physiochemical properties, analysis of the microstructure and the environment performance of the WDC were analyzed. In the meantime, the process of hydration of all products of non-autoclaved aerated concrete including WDC were studied by using XRD, FT-IR and SEM. The findings revealed that the benzene series of WDC is all non-detected, and the heavy metals’ results of single factor index method and potential ecological environment risk were all meet the standard. The contents of heavy metals in WDC are under the level of national standard. As well as, the WDC are rich in calcium, silicon and aluminium, and the particle size is concentrated in 30 μm. This chemical and particle characteristic makes them have the basic conditions as mineral admixtures. So, the optimum mixture ratio of aerated concrete is 2.7-13.6% for WDC, 13.6-27.3% for fly-ash, 20% for cement, 11.8% for quicklime and 1.8% for phosphogypsum, and premise condition is W/S is 0.62, curing temperature and time are 80 °C and 12 h, respectively. The unit weight together with the mechanical properties of the aerated concrete that has 40% WDC (instead of 40% fly-ash) all satisfy the B06, A3.5 GB/T11968-2006 standards. Other tests were carried out to determine its environmental performance. It established that the production of aerated concrete with 40% WDC does not result in any secondary contamination. Also, based on these properties of WDC aerated concrete we propose main technology and process route of the industrial practice.