为探索极细疏浚砂资源化利用的有效途径,分别采用振动成型及半干法压制成型方法,以不同含泥量(6.5%~25.8%)的长江下游极细疏浚砂(细度模数0.1~0.3)为主要原料制备水泥基材料替代普通混凝土。研究表明:在振动成型方法下,含泥量的增加对该材料耐久性、力学性能均有不利影响,低含泥量(6.5%)水泥基材料28 d抗压强度和劈裂抗拉强度分别可达35.1 MPa和3.98 MPa,抗冲磨强度和质量损失率分别可达12.5 h/(kg/m²)和8.4%;半干法成型方法下,含泥量的增加对水泥基材料强度增长有利,高含泥量(25.8%)水泥基材料28 d抗压、劈裂抗拉强度分别可达37.0 MPa和4.4 MPa,较振动成型方法下分别提高36.5%和25.7%。此外,以振动成型或半干法成型工艺制备的疏浚砂水泥基材料强度可靠,与普通C30混凝土相比,成本可降低33.0%~40.5%,环境友好,具有显著的生态效益。研究成果对于高效、科学、资源化利用长江下游极细疏浚砂有参考价值。

To explore an effective way of utilizing fine dredged sand as a replacement of ordinary concrete, cement-based material was prepared by using fine dredged sand with fineness modulus of 0.1-0.3 from the downstream of the Changjiang River as the main raw material. Dredged sand with varied mud content (6.5%-25.8%) was made into cement-based materials by adopting vibration and semi-dry pressing methods, respectively. In the vibration case, the increment of mud content has an adverse impact on the durability and mechanical properties of the tested material. The 28-day compressive strength and splitting tensile strength of cement-based materials with low mud content (6.5%) reached 35.1 MPa and 3.98 MPa, respectively, and the abrasion resistance strength and mass loss rate amounted to 12.5 h/(kg/m²) and 8.4%, respectively. In the semi-dry pressing case, however, the rising of mud content is conducive to the material strength. The 28-day compressive strength and splitting tensile strength of prepared materials with high mud content (25.8%) reached 37.0 MPa and 4.4 MPa, respectively, up by 36.5% and 25.7% respectively compared with those prepared by vibration method. Moreover, preparing cement-based material with vibration or semi-dry pressing molding techniques using dredged sand is environmental-friendly and of notable ecological effect by cutting the costs by 33.0%-40.5% compared with that using ordinary C30 concrete.