二氧化碳固化对透明混凝土在不同粘合剂和聚合物比率中的性能的影响
Mingfang Ba1, Siyi Fang1, Wei Cheng1
1School of Civil and Environmental Engineering, Ningbo University, No. 818 Fenghua Road, Ningbo 315211, China.
Materials (Basel, Switzerland)
|July 14, 2023
概括
早期的二氧化碳 (CO2) 固化可使混凝土的透气强度提高15-18%,在较高的料-聚合物比率下,效益更大. 这种方法可以提高机械性能,而不损害耐水性.
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
- 环境工程 环境工程
背景情况:
- 透水混凝土对于可持续的城市发展至关重要,可以控制雨水的流失.
- 优化透混凝土的性能需要了解材料组成和固化效应.
- 关于二氧化碳固化和糊剂-聚合物比率的综合影响的数据有限.
研究的目的:
- 为了研究早期二氧化碳 (CO2) 固化对透式混凝土性能的影响.
- 为了在二氧化碳固化下比较性能,与未碳化的条件相比.
- 分析不同料-聚合物比率对二氧化碳固化透水混凝土的影响.
主要方法:
- 机械性能测试 (强度).
- 测量水的透性和多孔性.
- 微结构分析 (毛孔大小分布).
- 化学成分分析. 化学成分分析.
主要成果:
- 早期的二氧化碳固化使混凝土的穿透强度增加了15-18%.
- 由于二氧化碳固化而产生的强度增强在较高的料-聚合物比率下更为显著.
- 二氧化碳固化并没有显著降低耐水性;碳化程度随着糊状聚合物比率的增加而降低.
- 二氧化碳固化减少了微孔 (<40 nm) 和增加了较大的孔 (>40 nm),与强度增加相关.
结论:
- 早期的二氧化碳固化是一种有效的方法,可以提高透式混凝土的机械强度.
- 糊状聚合物比率显著影响二氧化碳固化的有效性.
- 二氧化碳固化提供了一种可行的策略,可以在不牺牲透性的情况下提高透性混凝土的性能.
相关概念视频
01:18Porosity in Cement Paste
178
The porosity of concrete is a measure of the void spaces within its structure. These spaces impact its strength and durability significantly. When water and cement interact, a chemical reaction called hydration creates a semi-solid paste. This paste includes combined water, making up approximately 23% of the cement's dry mass, and gel water, which fills minuscule voids known as gel pores, accounting for about 28% of the cement gel volume.
The balance of water to cement in the mix is...
The balance of water to cement in the mix is...
178
01:23Pore Size Distribution
168
In concrete, the pore size distribution significantly influences the material's properties. Capillary pores, markedly larger than gel pores, form a vast network within partially hydrated cement paste, reducing the concrete's strength and increasing its permeability. This heightened permeability leads to a greater risk of damage from environmental factors like freeze-thaw cycles and chemical attacks, with the extent of vulnerability also being tied to the water-to-cement ratio.
Adequate...
Adequate...
168
01:20Curing of Concrete
121
The hydration of cement takes place within the water-filled capillary pores. However, environmental elements can disrupt this process by evaporating water from the concrete surfaces. Sealed concrete with a water-cement ratio below 0.5 experiences self-desiccation, leading to water loss. The water loss in concrete is mitigated by curing. This technique involves keeping the concrete saturated to maintain the necessary temperature and moisture conditions, to optimally fill the spaces in the cement...
121
01:24Carbonation Shrinkage
169
Atmospheric CO2 penetrates the concrete's pores and, in the presence of moisture, forms carbonic acid, which then reacts with calcium hydroxide in the hydrated cement, forming calcium carbonate. This process reduces the concrete's volume and is termed carbonation shrinkage.
The concrete's permeability is slightly reduced as calcium carbonate produced during the reaction fills its pores. Furthermore, its strength is slightly enhanced as the water released during the reaction...
The concrete's permeability is slightly reduced as calcium carbonate produced during the reaction fills its pores. Furthermore, its strength is slightly enhanced as the water released during the reaction...
169
01:25Permeability of Concrete
175
Permeability in the context of concrete refers to how easily liquids or gases can pass through the material. This quality is crucial for assessing the water-tightness and durability of concrete structures and their resistance to chemical attacks. Concrete permeability can be determined through comparative laboratory tests. These tests typically involve sealing a concrete specimen from the sides, applying water pressure to the top surface with pressure, and measuring the amount of water passing...
175
01:21Aggregate Cement Ratio
273
The Aggregate Cement ratio refers to the weight of aggregate divided by the weight of cement in a concrete mix. Altering this ratio has profound effects on the concrete's properties. This ratio plays a pivotal role in determining the strength, workability, and durability of concrete. When the Aggregate Cement ratio is higher, the mix is leaner, meaning it has less cement paste to lubricate the aggregate, potentially making the concrete less workable. Such mixes, known as lean, enhance the...
273