关键词: 长江疏浚砂, 水泥基材料, 含泥量, 工程性能, 成型工艺

Abstract: 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.

Key words: dredged sand from Changjiang River, cement-based materials, mud content, engineering properties, molding techniques