Study on High-degree Recycled Aggregate for Concrete

混凝土用高等级再生骨料的研究

• 批准号: 13650639
• 负责人: KASAMI Hideo
• 金额: $ 1.98万
• 依托单位: Kogakuin University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650639/
• 关键词: recycled aggregate; heating & grinding method; oven dry specific gravity; water absorption; concrete; self-compacting concrete; strength; durability; コンクリート; 絶乾密度; 静弾性係数; 乾燥収縮; 中性化; 凍結融解; 高品質再生骨材; 副産微粉; 調合

This report presents the results of series of studies conducted to determine the quality of high degree recycled aggregate made with heating & grinding method and its effects on normal and self-compacting concrete.High-degree recycled aggregates, made with heating and grinding method and free of adhered mortar on aggregate particles, satisfied the requirements for normal aggregates of Japanese Architectural Standard Specification JASS 5 for Reinforced Concrete work. Recycled aggregates, made with mechanical grinding method did not meet with the requirement of JASS 5 for normal aggregate, oven dry specific gravity being less than 2.4g/cm^3 and water absorption being higher than 4.0%due to adhered mortar, which causes deteriorating effects on drying shrinkage and durability of concrete. The allowable maximum value of adhered mortar content was found to be 15% for the specified oven dry specific gravity of 2.5g/cm^3 and water absorption of 3.0%. Concrete containing high-degree recycled ag … More gregates with higher percentage of solid volume as much as river gravel has the equivalent strength and durability as those with crushed stone. And water content and drying shrinkage were lower and modulus of elasticity of concrete was higher than those of crushed stone concrete. High-degree recycled aggregate was found to be applicable for self-compacting concrete, with higher fluidity, lower binder content, lower dosage of super-plasicizer, lower drying shrinkage and higher modulus of elasticity than those of crushed stone concrete. By-product powder with the fineness of 400m^2/kg generated in the process of heating & and grinding can be applicable as additives for self-compacting concrete without significant adverce effects on concrete quality.Series of experimental studies were carried out to determine the properties of concrete containing high quality recycled aggregates on normal concrete and super-plasticized high-performance concrete. High quality recycled aggregate concretes showed lower water content than those with crushed stone of the same slump. Compressive strengths were equivalent to those with river gravel of the same water cement ratio and were 10% lower than those with crushed stone. Tensile strengths and moduli of elasticity were higher and drying shrinkage were lower than those with crushed stone. Less

本报告介绍了一系列研究的结果，以确定用加热和研磨方法制成的高程度再生骨料的质量及其对普通混凝土和自密实混凝土的影响。用加热和研磨方法和免费方法制成的高程度再生骨料骨料颗粒上粘附砂浆的含量，满足日本建筑标准规范 JASS 5 钢筋混凝土工程对普通骨料的要求。采用机械研磨方法制造的再生骨料不符合 JASS 5 钢筋混凝土工程的要求。普通骨料，烘干比重小于2.4g/cm^3，因粘结砂浆而吸水率高于4.0%，对混凝土干燥收缩和耐久性能造成影响，粘结砂浆含量允许最大值为对于指定的烘干比重为 2.5g/cm^3、吸水率为 3.0% 的含有高比例再生骨料的混凝土，其含量为 15%。与河卵石相比，其强度和耐久性与碎石混凝土相当，且含水量和干燥收缩率低于碎石混凝土，弹性模量高于碎石混凝土。适用于自密实混凝土，与细度的碎石粉混凝土相比，具有较高的流动性、较低的粘结剂含量、较低的超塑化剂用量、较低的干燥收缩和较高的弹性模量。加热研磨过程中产生的400m^2/kg可作为自密实混凝土的添加剂，对混凝土质量没有明显影响。通过一系列的试验研究，确定了含有优质再生骨料的混凝土的性能优质再生骨料混凝土的含水量低于相同坍落度的碎石，其抗压强度与相同水灰比的河卵石相当。比碎石低10%，拉伸强度和弹性模量比碎石高，干燥收缩率低。