Difficulty: Easy
Correct Answer: Tri-calcium silicate (C3S)
Explanation:
Introduction / Context:
Rapid hardening cement (RHC) is specified where early strength is required, such as precast elements and urgent repairs. Its chemistry is tuned to accelerate strength gain in the first 1–7 days.
Given Data / Assumptions:
Concept / Approach:
Increasing tri-calcium silicate (C3S) and grinding fineness enhances hydration rate, producing more calcium-silicate-hydrate quickly, hence higher early compressive strength. C2S contributes later-age strength; C3A affects setting and heat evolution.
Step-by-Step Solution:
Verification / Alternative check:
Strength–age curves in cement handbooks show RHC surpassing OPC at early ages due to elevated C3S and fineness.
Why Other Options Are Wrong:
Common Pitfalls:
Confusing rapid-hardening with quick-setting cement; the former focuses on early strength, the latter on accelerated set.
Final Answer:
Discussion & Comments