Bottom vacuum preloading (BVP) is the method of applying vacuum pressure at the bottom zone of soils to generate pore-water pressure difference between the top and bottom boundaries, thereby achieving the consolidation drainage. This study conducted a large-size model test to explore the engineering feasibility of combining self-weight and BVP to treat construction waste slurry (CWS). Through the treatment of the measures of self-weight consolidation (0-26 d) and BVP with a water cover (26-78 d), the average water content of CWS declined from 255.6% to 115.9%, and the volume reduction ratio reached 0.476. However, since these two measures could properly treat only the bottom CWS, the measures of BVP with the mud cover (78-141 d) and the natural air-drying (141-434 d) were performed to further decrease the CWS water content near the upper zone. The latter two-stage measures reduced the average water content of CWS to 84.9% and increased the volume reduction ratio to 0.581. Moreover, the measurements suggested that the treated CWS largely exhibited a shear strength of 10 kPa or more. Overall, the proposed approach appeared some engineering feasibility to treat CWS, and the performed test study could act as a reference for the practical treatment of CWS.

A large quantity of waste slurry (WS) is produced during the process of drilled grouting piles, which is mainly composed of bentonite, clay, and metal ions. Improper disposal of WS will bring about serious environmental problems. In this study, flocculation technology and solidification technology were combined to treat WS using three types of flocculant solution, and waste slurry geopolymer concrete (WS-GPC) was prepared using treated WS, slag powder (SP), fly ash (FA) and alkali activator. The results showed 100 mL WS treated with 25 mL APAM flocculant solution with a concentration of 0.1 % had the lowest filtrate turbidity and the lowest mud moisture content (50.30 %). The bone-glue ratio, sand rate and water-to-cement ratio of the concrete samples was 3.0, 0.4 and 0.42, respectively. Taking into account the 7-day compressive strength of WS-GPC and the maximum application rate of WS, the optimal slurry cake content was 35 %. At this time, the total amount of slag powder and fly ash used was 65 %. The effects of slag powder dosage (SPD), alkali activator dosage (AAD), and alkali activator modulus (AAM) on the compressive, flexural, and splitting properties of WS-GPC were discussed. And X-ray diffraction (XRD), scanning electron microscope (SEM), and mercury intrusion porosimetry (MIP) tests were also taken to analyze the phase composition, microstructure, and pore structure of WS-GPC. There was a positive correlation between the mechanical strength of WS-GPC and SPD. While when the AAD or AAM increased, the mechanical strength of WS-GPC first increased followed by a decrease. The mechanical properties of WS-GPC with 60 % SSD, 29 % AAD and AAM being 1.3 were optimal due to more hydration products, smoother and denser microstructure, lower porosity and smaller average pore diameter of the WS-GPC. This study is expected to create a new way of green treatment of WS and provide a theoretical basis for the application of WS-GPC.