使用成熟度方法预测混凝土压力强度的评估,包括各种固化温度和粘合剂成分
Gum-Sung Ryu1, Gi-Hong An1, Yong-Sik Yoon2
1Department of Structural Engineering Research, Korea Institute of Civil Engineering and Building Technology, Goyang 10223, Republic of Korea.
Materials (Basel, Switzerland)
|December 17, 2024
概括
预测混凝土的压力强度在20°C和40°C固化温度下更准确. 期限方法与强度到期关系相结合,有效地预测特定条件下的具体强度.
科学领域:
- 土木工程 土木工程是指土木工程.
- 材料科学 材料科学 材料科学
- 建筑技术 建筑技术 建筑技术
背景情况:
- 普通波特兰水泥 (OPC) 是混凝土中的主要粘合剂.
- 地质颗粒高炉渣 (GGBFS) 和飞灰是用于增强混凝土性能的补充水泥材料 (SCM).
- 混凝土的压力强度发展受到固化温度,粘合剂含量和SCM混合物比率的影响.
研究的目的:
- 系统地分析固化温度,粘合剂含量和GGBFS/飞灰比对混凝土压力强度的影响.
- 用成熟度方法评估混凝土的强度特征,在20°C时正常化为28天.
- 开发和验证基于成熟度的混凝土压力强度的预测模型.
主要方法:
- 对混凝土混合物的实验研究,其OPC,GGBFS和飞灰比例各不相同.
- 应用成熟度方法来估计混凝土强度的发展.
- 开发一种强度-成熟度关系模型来预测压力强度.
- 对实验数据的分析,以获得关键变量的强度系数.
主要成果:
- 使用成熟度方法开发了混凝土压力强度的预测模型.
- 高预测精度 (R2>0.90) 和低误差率 (<10%) 在20°C和40°C的固化温度下实现.
- 在5°C的低固化温度下观察到更低的精度和更高的错误率.
- 该模型有效地预测了在特定固化和粘合剂设计条件下的强度.
结论:
- 成熟度方法,加上强度成熟度关系,为预测混凝土压力强度提供了有效的工具.
- 固化温度显著影响强度预测的准确性;在中度至高温下观察到最佳性能.
- 这些发现支持优化混凝土混合设计和通过预测强度分析进行质量控制.
相关概念视频
01:20Strength of Cement
122
Strength tests for cement are not performed directly on neat cement paste due to difficulty in obtaining consistent, reliable specimens. Instead, cement is typically tested in the form of cement-sand mortar.
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in...
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in...
122
01:14Design Example: Managing Concrete Workability
72
This example deals with managing the workability of concrete for a raft foundation project under hot weather conditions. Workability is crucial for ensuring the concrete is easy to place, compact, and finish. In this scenario, a slump test — a common method to measure the workability of fresh concrete — initially indicated low workability. This was attributed to the rapid water loss from the concrete mix, exacerbated by the high temperatures causing the course aggregates to heat up.
72
01:27Cold Weather Concreting
56
When freshly poured concrete is exposed to freezing temperatures before it has set, the water within the concrete can freeze. This expansion disrupts the setting process, delays chemical reactions necessary for hardening, and increases the volume of pores within the hardened concrete, which weakens its overall structure. If the concrete manages to reach an appreciable strength before it freezes, the damage can be somewhat mitigated.
To counteract the negative impacts of cold weather, ensuring...
To counteract the negative impacts of cold weather, ensuring...
56
01:20Hot Weather Concreting
53
Concreting at elevated temperatures accelerates the hydration process, leading to quicker setting but potentially reducing the long-term strength of the concrete structure. Additionally, low air humidity fosters rapid moisture loss from the concrete, resulting in reduced workability, pronounced plastic shrinkage, and a higher likelihood of crazing.
Mitigating the heat increase in concrete can be economically achieved by shading aggregate stockpiles to prevent heating from solar radiation,...
Mitigating the heat increase in concrete can be economically achieved by shading aggregate stockpiles to prevent heating from solar radiation,...
53
01:14Testing Water Quality
103
When the quality of water for concrete preparation is uncertain, its impact on the setting time of cement and compressive strength of mortar is assessed by comparison with de-ionized or distilled water benchmarks. American Society for Testing and Materials (ASTM) C1602 requires the setting times to be within 90 minutes of the control, British Standard (BS) 3146:1980 allows a 30-minute variance in the initial setting, while British Standards European Norm (BS EN) 1008 specifies initial setting...
103
01:29Frost Resistant Concrete
74
Concrete's susceptibility to frost damage during freeze-thaw cycles demands strategic measures to enhance its frost resistance. Employing techniques like air entrainment, adjusting the water-cement ratio, proper curing, and selecting appropriate aggregates are essential.
Introducing microscopic air bubbles into the concrete mix through air entrainment creates small voids that accommodate ice expansion, thereby reducing internal pressures and preventing cracking. The optimal amount of...
Introducing microscopic air bubbles into the concrete mix through air entrainment creates small voids that accommodate ice expansion, thereby reducing internal pressures and preventing cracking. The optimal amount of...
74