Cement must exhibit a compressive strength of at least 110 kg/cm2 after three days and 170 kg/cm2 after seven days. Ordinary cement should have a turbidimetric fineness of approximately ________________ cm2/g?
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Answer: B. 1600
Explanation
Ordinary Portland cement should possess a turbidimetric fineness of approximately sixteen hundred square centimeters per gram. Fineness measurements quantify the specific surface area of cement particles available for chemical hydration. This specified particle size distribution ensures proper setting rates and early strength development in concrete. Cement fineness is measured using turbidimetric or air permeability apparatus to determine average particle size. Finer cement particles hydrate more rapidly because water has a larger surface area to react with initially. Grinding clinker to the correct fineness represents an energy-intensive step in cement manufacturing plants.
Civil engineering standards require strict quality control of cement fineness to guarantee structural design strength. High early strength cements are ground even finer to accelerate hydration reactions in urgent construction work. Proper storage of cement powder prevents moisture absorption and premature particle agglomeration before use. A fineness value of eight hundred square centimeters per gram is too coarse for standard ordinary portland cement. A value of four thousand square centimeters per gram describes much finer rapid-hardening specialty cements. Eighty-five hundred square centimeters per gram exceeds normal commercial grinding specifications for standard cement.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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