Chun Zhang’s scientific contributions

The feasibility of coordinated use of water-based drilling cuttings (WDC), fly ash, and phosphogypsum (PG) as raw materials for the preparation of WDC non-autoclaved aerated concrete (WNAAC) was evaluated by laboratory experiment. The results showed that the pozzolanic reaction of the multi-component cementitious system containing 40% (in mass) of WDC is significantly promoted. Newly formed C-S-H gel and ettringite with the uniform distribution of fibrous and flake-like shape occur, presenting a denser and interlock microstructure. In addition, after cured by steam at 80 °C for 24 h, the mechanical property and unit weight of the WNAAC prepared with 40% WDC fully meet the B06, A3.5 grade of China state standard (GB/T11968-2006). Environmental performance tests confirm that the WNAAC prepared with 40% WDC does not create any secondary contamination.

Phosphogypsum (PG) accumulation occupies huge amounts of land resources and results in serious environmental risks. A new recycling product, the phosphogypsum embedded filler (PGEF) made with calcination-modified phosphogypsum, was developed. The preparation process, hydration mechanism of PG, basic physical performances, environmental safety, engineering application, and cost analysis of the PGEF were studied. The results showed that the stress performance and thermal insulation property of the products were satisfied. Environmental performance tests established their findings that the application of PGEF prepared with calcination-modified PG does not cause any secondary contamination. In addition, the cost of PGEF is far lesser than that of the same volume of reinforced concrete. PGEF prepared with calcination-modified PG has shown a perfect application in cast-in situ concrete hollow floor structure.

This research involved randomly choosing 155 sets of experimental data that were collected from building companies. These sets of data were the result of lime analyses by sucrose titration done within 12 months by the laboratory attendants. The results of this experimental data were then gathered to be analyzed using the linear fitting formula. The results indicate that the analysis can accurately determine quicklime’s effective calcium content by regression analysis using the digestion temperatures. In addition, the X-ray diffraction method was used to test the quicklime’s calcium content, which verified that the method of linear fitting has good representativeness and practicability. This can greatly optimize the traditional process and has the prospect of being used widely.

The exploration and development of shale gas technology provide a way to utilize clean fuels with high efficiency and minimum environmental impact. However, the accumulation of water-based drilling cuttings (WDC) from oil and gas field development is causing serious waste of land resources and environmental safety problems. This work presents an experimental study on the feasibility of recycling original WDC as replacements for fine aggregates and as part of cementitious materials for the manufacture of non-fired bricks. Mechanical and physical properties, detailed environmental performance, and microstructure analysis were carried out. Meanwhile, the original hydrated products and hydration process of WDC brick were evaluated with, FT-IR (Fourier transform infrared), XRD (X-ray diffraction), SEM (scanning electron microscopy) and EDX (energy-dispersive X-ray spectroscopy). The outcomes indicated that WDC have certain pozzolanic characteristic and a significant impact on the durability and strength of non-fired bricks. The best properties achieved with the help of 50% WDC which meet grade M10 according to a Chinese standard (GB/T2542-2012). Environmental performance tests provides that the WDC used as the raw material for non-fired bricks, and from the technical point of view, does not have environmental pollution.

The overall objective of this research project was to investigate the heavy metals environmental security control of resource utilization of shale gas’ drilling cuttings. To achieve this objective, we got through theoretical calculation and testing, ultimately and preliminarily determine the content of heavy metals pollutants, and compared with related standards at domestically and abroad. The results indicated that using the second Fike’s law, the theoretical model of the release amount of heavy metal can be made, and the groundwater environmental risk as main point compared with soil. This study can play a role of standard guidance on environmental security control of drilling cuttings resource utilization by the exploration and development of shale gas in our country.