HU Ming-yu, CAI Guo-jun, XU Wang-min, HU Biao
In the light of sponge city construction and solid waste resource utilization, we prepared ecological building material using copper mine tailings and bentonite as filler, recycled sintered bricks as aggregate, and cement as cementitious material. The material has functions of absorption, storage, infiltration and purification. We further optimized the mix proportion of the material through orthogonal experiment and investigated the plant growth and water purification effects of the material at optimum mix ratio. Results demonstrate that with a 15% and 7.5% dosage of copper mine tailings and bentonite, respectively, and a water cement ratio at 0.90, the functional eco-material boasts a 28-d compressive strength over 4.0 MPa, permeability coefficient greater than 4.0 cm/s, and water absorption more than 21.0%. The material also has good effect in cultivating Puccinellia distans Parl. and folium Ilex chinensis by mud mulching method, which can be used for water conservancy project and sponge city construction respectively. Filtered by the material, SS, COD, TP, and NH3-N reduces by 53.3%, 29.6%, 51.9%, and 25.6%, respectively. The purification effect of the material after plant cultivation is stronger for water-soluble impurities. Theoretically, substances such as TP and NH3-N adsorbed by the material are more beneficial to vegetation growth.
