使用不同pH值的经过处理的家用废水对自压缩混凝土的可加工性,机械性和耐久性质的影响
Shirin Keneshlo1, Gholamreza Asadollahfardi2, Peyman Homami1
1Civil Engineering Department, Faculty of Engineering, Kharazmi University, Tehran, Iran.
Environmental science and pollution research international
|January 5, 2024
概括
在自压缩混凝土 (SCC) 中使用经过处理的家用废水略微降低了机械强度,并增加了水吸附. 废水的性pH值与酸性条件相比,产生更好的混凝土性能,较低的Ca/Si比率与较高的压力强度相关.
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:
- 可持续的建筑实践对于减少环境影响至关重要.
- 在混凝土中再利用废水为节水提供了一个潜在的解决方案.
- 处理废水pH值对混凝土性能的影响需要详细研究.
研究的目的:
- 评估各种pH级别的经过处理的家用废水对自压缩混凝土 (SCC) 的可加工性,机械性和耐久性能的影响.
- 用处理过的废水进行的SCC的性能与使用自来水的对照样本进行比较.
主要方法:
- 设计了8种SCC混合物,包括2种用自来水和6种用不同pH值的经过处理的家用废水进行控制.
- 进行了标准测试,以评估可加工性,压力强度,屈曲强度,断裂性,碳化和水吸附.
- 使用能量分散光谱 (EDS) 和扫描电子显微镜 (SEM) 来分析微观结构变化.
主要成果:
- 与性相比,与酸性处理废水相比,SCC的可行性更高.
- 使用经过处理的废水,压力强度,屈曲强度和断裂性降低了不到10%.
- 在用经过处理的废水制成的SCC样本中,碳化和水吸附 (30分钟和毛细血管) 增加.
- 在酸性条件下压缩强度的降低大约比性条件下大约5% .
- 在使用经过处理的废水时,EDS和SEM显示了Ca/Si比率的增加,与压力强度降低相关.
结论:
- 经过处理的家用废水可以用于SCC,但它会对机械性能和耐用性产生负面影响.
- 性处理废水导致更好的SCC性能 (更高的压力强度) 由于较低的Ca/Si比率.
- 需要进一步的研究,以优化在混凝土生产中使用经过处理的废水.
更多相关视频
相关概念视频
Testing Water Quality
111
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...
111
Quality of Water
96
In concrete preparation, the quality of water is paramount as it affects the strength and durability of the concrete. Potable water is usually preferred; however, it must not have excessive sodium or potassium to prevent compromising the concrete's integrity. Water quality is typically evaluated based on impurities such as dissolved solids, chlorides, and sulfates, and its pH value is ideally between 6 and 8. Even slightly acidic natural water may be acceptable unless it contains harmful...
96
Acid Attack on Concrete
217
When acids come into contact with concrete, they initiate a chemical reaction that dissolves the hydrated cement paste. This process leads to softening and structural weakening of the concrete. This issue is commonly observed in environments such as chimneys, sewers, and industrial settings. The severity of the damage increases as the pH of the water interacting with the concrete drops below 6.5. In particular, a pH under 4.5 can cause significant concrete damage.
The rate at which hydrogen...
The rate at which hydrogen...
217
Workability of Concrete
105
The workability of concrete is a crucial property that affects its handling, placing, and finishing during construction. It describes the ease with which concrete can be mixed, placed, compacted, and finished. Workability is primarily concerned with the concrete's movement and its ability to resist internal friction and external resistance from molds and reinforcements during the application process.
Concrete's workability is determined by its resistance to internal forces that arise...
Concrete's workability is determined by its resistance to internal forces that arise...
105
Design Example: Managing Concrete Workability
81
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.
81
Effect of Sea Water on Concrete
242
Concrete exposed to seawater can undergo degradation like the dissolution of ettringite and gypsum, increasing the material's porosity and decreasing its strength. In contrast, the crystallization of salts within the concrete's pores can cause expansion, particularly above the waterline where evaporation occurs. Nonetheless, this expansion only happens when seawater, enabled by the concrete's permeability, manages to infiltrate the structure.
Concrete in areas between tide marks,...
Concrete in areas between tide marks,...
242


