两相悬浮体系下机制砂自密实混凝土性能设计

Performance Design of Self-compacting Concrete Incorporated with Crushed Sand Based on Two-Phase Suspension System

摘要:

将机制砂自密实混凝土视为粗骨料加砂浆的固液两相悬浮体系，设计了4组基础砂浆来制备机制砂自密实混凝土，每组在1.5~2.9 mm范围内设置8种砂浆膜厚，研究了基础砂浆流变特性、强度及膜厚对机制砂自密实混凝土工作性能和力学性能的影响，建立了基于基础砂浆性能及膜厚的机制砂自密实混凝土性能预测公式.结果表明：为保证机制砂自密实混凝土的工作性能和力学性能，其优化砂浆膜厚范围为1.9~2.3 mm，对应的基础砂浆最大初始屈服剪切应力范围为51.9~65.2 Pa；预测公式拟合相关系数均达0.90以上，相关性显著.

Abstract:

Self-compacting concrete（SCC） is regarded as a two-phase suspension system consisting of coarse aggregate and mortar. Four groups of basic mortars prepared by crushed sand were designed to prepare SCC， which had eight mortar film thicknesses ranging from 1.5 mm to 2.9 mm. The effects of the mortar rheological properties， strength and film thickness on the workability and mechanical properties of the SCC were investigated. The performance prediction formulas for SCC based on mortar properties （initial yield shear stress of the fresh mortar and strength of the hardened mortar） and film thicknesses were established. The results show that to ensure the workability and mechanical properties of the SCC incorporated with crushed sand， the optimized mortar film thickness ranges from 1.9 mm to 2.3 mm， corresponding to a basic mortar maximum initial yield stress range from 51.9 Pa to 65.2 Pa； the predictive formulas exhibit significant correlation， with correlation coefficients exceeding 0.90.