Strength of concrete shows an increase with ...........
Try it first: pick an option, then read the explanation.
Correct answer: B. Increase in rate of loading
Concrete Strength vs Rate of Loading
When concrete is loaded faster, fewer micro-cracks can initiate and propagate before the failure load is reached. The material has less time to deform and redistribute stress, so it appears stronger. Conversely, a slow rate of loading allows creep and micro-cracking to develop, reducing the apparent strength.
This is similar to how many brittle materials behave: dynamic loading gives higher apparent strength than static loading.
Strength increases with increasing rate of loading — option B.
Key takeaway
Faster loading → less time for micro-cracking → higher apparent strength. Impact loading gives the highest values; sustained static load gives the lowest.