基于胶浆特性的透水混凝土强度及抗冻性研究

Investigation on the Strength and Freeze-Thaw Resistance of Pervious Concrete Based on the Properties of Cement Paste

透水混凝土的强度和抗冻性是影响其在重荷载交通道路和寒冷地区推广应用的关键性能。本工作研究了胶浆工作性能、强度、界面粘结性能及透水混凝土强度、抗冻性,并揭示了影响透水混凝土性能的主要因素。结果表明,通过最大浆集比可以评价胶浆和透水混凝土的工作性能,且当最大浆集比与设计浆集比接近时,透水混凝土的工作性能最佳。未改性胶浆界面冻融前后均发生粘结破坏。而改性胶浆未冻融时界面拉拔强度提升67%~156%,发生内聚破坏;冻融后界面拉拔强度显著降低,发生内聚、粘结混合破坏。工作性能良好的透水混凝土抗压强度为38.2~40.3 MPa,抗折强度为3.8~4.3 MPa,透水系数为2.85~2.92 mm/s。主成分分析结果表明,各因素对透水混凝土性能影响的占比依次为:界面性能、胶浆配合比、空隙特征共占44.8%,胶浆裹覆性能占27.5%,胶浆强度占20.0%。

The strength and the freeze-thaw resistance of pervious concrete are key properties for its application in heavy-load traffic roads and cold regions. The workability, the strength and the interfacial adhesion of cement paste as well as the strength and the freeze-thaw resistance of pervious concrete were investigated, and the main factors affecting the performance of pervious concrete were revealed. The results show that the wor-kability of paste and pervious concrete can be evaluated by the maximum paste-aggregate ratio, and good workability of pervious concrete can be obtained when the maximum paste-aggregate ratio is close to the designed paste-aggregate ratio. The adhesive damage occurs whether freeze-thaw tests are performed on the unmodified paste or not. On the contrary, the pull-off strength of the modified paste is 67% to 156% higher than that of the unmodified paste without freeze-thaw tests, with cohesive damage occurring, while it is significantly reduced after freeze-thaw tests, with both cohesive damage and adhesive damage appearing. The compressive strength of the pervious concrete with good workability is 38.2—40.3 MPa, the flexural strength is 3.8—4.3 MPa, and the permeability coefficient is 2.85—2.92 mm/s. The results of the principal component analysis show that the principal factors on the performance of pervious concrete are in order as follows: 44.8% for interfacial properties, mix design of paste and void characteristics, 27.5% for coating properties of paste, and 20.0% for the strength of paste.