Determining the optimum dosage of Ewende micro silica powder (silica fume) in UHPC can be considered from the following aspects:
Experimental studies
- designing the mixing ratios with different amounts of silica fume: preparing several sets of UHPC specimens, the amount of silica fume can be varied within a certain range, e.g., from 5% to 25% of the total amount of cementitious material.
- Performance test: Strength test (including compressive strength, flexural strength, etc.), durability test (impermeability, frost resistance, etc.), and workability test (fluidity, water secretion rate, etc.) are carried out on specimens with different mixing ratios.
- Data analysis: analyze the trend of various performance indicators of UHPC under different amounts of micro silica powder, and determine the range of micro silica powder when the performance is optimal.
Considering the characteristics of raw materials
- Cement variety and quality: Different cements have different adaptability to micro silica powder. For example, high grade cement usually works better with micro silica powder, but the dosage requirement of micro silica powder may also be different.
- Other admixtures: If other admixtures such as fly ash, mineral powder, etc. are also used in UHPC, their compounding effect with micro silica fume needs to be considered. The type and amount of these admixtures will affect the optimum amount of micro silica powder.
Engineering requirements
- Strength requirements: If the project requires very high strength of UHPC, it may be necessary to appropriately increase the amount of micro silica powder to improve the strength. However, it should also be considered that too high a dosage of micro silica powder may bring negative effects, such as a decline in working performance. 2.
- Durability requirements: For projects in harsh environments, such as marine environments, freezing and thawing areas, higher durability is required, and the dosage of micro silica powder may need to be adjusted to meet the durability requirements.
Reference to existing experience and standards
- Check the relevant literature and engineering cases: to understand the use of micro silica powder in similar projects and the optimal dosage range, in order to determine the dosage of micro silica powder in the current project to provide a reference.
- Follow relevant standards and codes: Some industry standards and codes may give guidance on the amount of micro silica powder to be used in UHPC.
In conclusion, to determine the optimal dosage of micro silica powder in UHPC, it is necessary to take into account the experimental research, raw material properties, engineering requirements, as well as the existing experience and standards and other factors, and to determine the most suitable dosage through continuous testing and optimization.