Performance-Based Specifications of Workability Characteristics of Prestressed, Precast Self-Consolidating Concrete-A North American Prospective.
Performance-Based Specifications of Workability Characteristics of Prestressed, Precast Self-Consolidating Concrete-A North American Prospective.
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基于性能的预应力预制自密实混凝土和易特性规范——北美展望
DOI：
10.3390/ma7042474
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发表时间：
2014-03-27
期刊：
影响因子：
--
通讯作者：
Han NX
中科院分区：
文献类型：
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作者：
Long WJ;Khayat KH;Lemieux G;Hwang SD;Han NX
充分选择材料成分和试验方法对于硬化混凝土的工作性规范和性能是必要的。进行了一项实验计划，以评估各种测试方法的适用性和工作性评估，并提出性能规格的预应力混凝土。总共有33个自固结混凝土（SCC）混合物与各种混合物配比参数，包括最大尺寸和类型的骨料，类型和含量的粘合剂，和w/cm进行了评估。建立了各种试验结果之间的相关性，用于评估和易性响应。建议自密实混凝土的坍落流动值为635-760 mm。为确保适当的填充能力大于80%，此类混凝土应具有通过能力，对应于L-箱阻塞比（h2/h1）≥ 0.5，J-环流动为570-685 mm，坍落流动减去J-环流动直径≤75 mm。此外，稳定的SCC应形成低于5%的柱偏析指数，对于与12.5或9.5 mm MSA成比例的SCC，30 min时的沉降速率为0.27%/h。建议对于用碎骨料和砾石制成的混凝土，SCC应分别具有100-225 Pa·s和100-400 Pa·s的塑性粘度，以确保适当的和易性。
Adequate selection of material constituents and test methods are necessary for workability specifications and performance of hardened concrete. An experimental program was performed to evaluate the suitability of various test methods for workability assessment and to propose performance specifications of prestressed concrete. In total, 33 self-consolidating concrete (SCC) mixtures made with various mixture proportioning parameters, including maximum size and type of aggregate, type and content of binder, and w/cm were evaluated. Correlations among various test results used in evaluating the workability responses are established. It is recommended that SCC should have slump flow values of 635–760 mm. To ensure proper filling capacity greater than 80%, such concrete should have a passing ability that corresponds to L-box blocking ratio (h2/h1) ≥ 0.5, J-Ring flow of 570–685 mm, slump flow minus J-Ring flow diameter ≤75 mm. Moreover, Stable SCC should develop a column segregation index lower than 5%, and rate of settlement at 30 min of 0.27%/h for SCC proportioned with 12.5 or 9.5 mm MSA. It is recommended that SCC should have a plastic viscosity of 100–225 Pa·s and 100–400 Pa·s for concrete made with crushed aggregate and gravel, respectively, to ensure proper workability.