以陶瓷基快速修补特种水泥作为试验材料,制作与大型机场道面板厚度相近的直径20cm、高40cm圆柱体水泥砂浆试件,检测试件中心温度随垂直方向沿时间的变化规律,并设置降低拌和水温度、加入硼砂缓凝剂、表层保温、材料预冷、降低水灰比五...以陶瓷基快速修补特种水泥作为试验材料,制作与大型机场道面板厚度相近的直径20cm、高40cm圆柱体水泥砂浆试件,检测试件中心温度随垂直方向沿时间的变化规律,并设置降低拌和水温度、加入硼砂缓凝剂、表层保温、材料预冷、降低水灰比五种温控试验方法。统计并计算各试验组的峰值温度、最大温差、温度应力及抗折强度等参数。试验结果显示,各试验组最大温度应力分别为4.69 MPa、5.15 MPa、4.56 MPa、5.18 MPa、4.14 MPa,相比于对照组分别降低4.2%、−5.2%、7.0%、−5.6%、15.5%。因此降低水灰比是降低温度应力的有效措施,建议在现场施工过程中使用高效减水剂以减少拌和水用量并提高混凝土和易性,同时根据环境条件及使用需求采用多种温控措施组合的方式以防止道面开裂。Ceramic-based rapid repair special cement was used as the test material to make cylindrical cement mortar specimens with a diameter of 20 cm and a height of 40 cm, which were similar to the thickness of the pavement panels of large airports. The central temperature of the specimens was tested along the vertical direction with time. Five temperature control test methods were set, including lowering the mixing water temperature, adding borax retarder, surface insulation, material precooling, and reducing the water-cement ratio. The peak temperature, maximum temperature difference, temperature stress, and flexural strength of each test group were statistically calculated. The test results showed that the maximum temperature stress of each test group was 4.69 MPa, 5.15 MPa, 4.56 MPa, 5.18 MPa, and 4.14 MPa, respectively, which were 4.2%, −5.2%, 7.0%, −5.6%, and 15.5% lower than those of the control group, respectively. Therefore, reducing the water-cement ratio is an effective measure to reduce temperature stress. It is recommended that a high-efficiency water reducer be used during on-site construction to reduce the amount of mixing water and improve the workability of concrete. At the same time, a combination of multiple temperature control measures should be used according to environmental conditions and usage requirements to prevent pavement cracking.展开更多
文摘以陶瓷基快速修补特种水泥作为试验材料,制作与大型机场道面板厚度相近的直径20cm、高40cm圆柱体水泥砂浆试件,检测试件中心温度随垂直方向沿时间的变化规律,并设置降低拌和水温度、加入硼砂缓凝剂、表层保温、材料预冷、降低水灰比五种温控试验方法。统计并计算各试验组的峰值温度、最大温差、温度应力及抗折强度等参数。试验结果显示,各试验组最大温度应力分别为4.69 MPa、5.15 MPa、4.56 MPa、5.18 MPa、4.14 MPa,相比于对照组分别降低4.2%、−5.2%、7.0%、−5.6%、15.5%。因此降低水灰比是降低温度应力的有效措施,建议在现场施工过程中使用高效减水剂以减少拌和水用量并提高混凝土和易性,同时根据环境条件及使用需求采用多种温控措施组合的方式以防止道面开裂。Ceramic-based rapid repair special cement was used as the test material to make cylindrical cement mortar specimens with a diameter of 20 cm and a height of 40 cm, which were similar to the thickness of the pavement panels of large airports. The central temperature of the specimens was tested along the vertical direction with time. Five temperature control test methods were set, including lowering the mixing water temperature, adding borax retarder, surface insulation, material precooling, and reducing the water-cement ratio. The peak temperature, maximum temperature difference, temperature stress, and flexural strength of each test group were statistically calculated. The test results showed that the maximum temperature stress of each test group was 4.69 MPa, 5.15 MPa, 4.56 MPa, 5.18 MPa, and 4.14 MPa, respectively, which were 4.2%, −5.2%, 7.0%, −5.6%, and 15.5% lower than those of the control group, respectively. Therefore, reducing the water-cement ratio is an effective measure to reduce temperature stress. It is recommended that a high-efficiency water reducer be used during on-site construction to reduce the amount of mixing water and improve the workability of concrete. At the same time, a combination of multiple temperature control measures should be used according to environmental conditions and usage requirements to prevent pavement cracking.
