高温对MICCP和EICCP生物水泥砂压力强度的影响
Rishabh Junwale1, Snigdha P Bhutange2, Madhuwanti Latkar3
1Department of Civil Engineering, Visvesvaraya National Institute of Technology (VNIT), Nagpur, Maharashtra, 440010, India. rishabh.junwale@gmail.com.
Molecular biotechnology
|January 29, 2025
概括
生物水泥建筑材料保持强度高达300°C,但性能在450°C以上显著下降. 这项研究评估了在高温和冷却方法下微生物和酶诱导的生物凝固.
科学领域:
- 可持续建筑材料科学 可持续建筑材料科学
- 在土木工程中的生物技术.
背景情况:
- 使用微生物或酶诱导的碳酸沉的生物凝固,提高了基于水泥的材料的强度和耐用性.
- 有限的研究存在于生物水泥材料在高温下的性能.
研究的目的:
- 研究高温 (300°C,450°C,600°C) 对生物水泥样本压力强度的影响.
- 为了比较微生物诱导 (细菌) 与酶诱导 (西瓜种子) 生物凝固的热性能.
- 评估不同冷却技术 (自然,喷水,泡喷雾) 对火灾后强度的影响.
主要方法:
- 使用尿溶性细菌和西瓜种子制备生物水泥砂样本.
- 标本暴露在受控的高温下 (300°C,450°C,600°C).
- 热暴露样本的压力强度测试,采用不同的冷却方法.
主要成果:
- 生物水泥样本保持了高达300°C的显著压力强度,表现优于对照样本.
- 在450°C时,在生物水泥和对照标本之间没有观察到强度的实质差异.
- 在600°C,生物水泥样本的压力强度低于对照样本,这是由于密度更高的微观结构造成的.
结论:
- 生物水泥化为基于水泥的结构提供高达300°C的耐热性.
- 对于生物水泥砂,不建议在反应堆或烤箱等温度超过450°C的应用.
- 对受火灾影响的生物水泥结构的冷却策略进行进一步研究是有必要的.
更多相关视频
相关概念视频
01:20Strength of Cement
112
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...
112
01:20Hot Weather Concreting
46
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,...
46
01:20Microcracking in Concrete
85
Microcracking in concrete refers to the tiny cracks that can form within the material even before any external load is applied. These microcracks typically occur at the interface between the coarse aggregate and the hydrated cement paste, often as a result of differential volume changes prompted by variations in stress-strain behavior, as well as thermal and moisture movement. Initially, these microcracks remain stable and do not grow substantially until the concrete is stressed to about 30...
85
01:21Masonry in Cold and Hot Weather Conditions
64
In cold weather, masonry construction requires specific precautions to ensure mortar does not freeze before curing, as this can significantly weaken its strength and watertightness. Mortar temperature should be maintained between 60°F and 80°F to support proper hydration and curing. Below 40°F, mortar water must be heated, but should not exceed 120°F as high temperatures can reduce mortar's compressive and bond strength.
Other key practices include keeping masonry units...
Other key practices include keeping masonry units...
64
01:29Strength and Heat of Hydration
184
The hydration of cement is an exothermic reaction in which heat is generated as cement hydrates. This heat of hydration is critical to cement's strength development. The rate at which this heat is generated affects the temperature rise, with a majority of the heat being released early in the hydration process, half within the first three days, and about 75% within the first week.
The heat of hydration for each cement compound is significant; for instance, tricalcium aluminate (C3A) and...
The heat of hydration for each cement compound is significant; for instance, tricalcium aluminate (C3A) and...
184
01:22Mass Concreting
42
Mass concreting refers to the process of placing large volumes of concrete, such as in gravity dams. The heat generated during the cement hydration process and differential cooling rates within the concrete mass can lead to a temperature gradient, which can result in thermal cracks in the concrete mass.
To reduce the risk of such cracking, the concrete mix may incorporate low-heat cement and pozzolans to reduce the temperature rise. Pre-cooled angular aggregates and water-reducing admixtures...
To reduce the risk of such cracking, the concrete mix may incorporate low-heat cement and pozzolans to reduce the temperature rise. Pre-cooled angular aggregates and water-reducing admixtures...
42