Thank you very much for your answer. However, after the concrete is fully cured, the strength of the concret under wet and dry conditions should not be the same? You cannot imagine that a concrete building in raining day is stronger (may be weaker) than sunshine dray day's.
Ron is correct in his advice. All concrete will continue to gain in strength throughout its hardened life. This is in part due to to the unreacted cement particles within the mix. Not all of the cement reacts in the first 28 days and, in general, if water is in contact ith the concrete then it will migrate and react with any cement it can find. Andy Machon
Thank you very much, Ron and Ginger. If there is no cement left for continuous reaction with water, will the concrete have a constant strength? I thought that if the concrete constantly contacts with water such as bridge fundation, the strength would eventually decay over long period of time. Don't you think so?
In addition to the above, concrete and masonry which are somewhat porous will absorb water during rain. Thus, the load carried by the structure will be marginally higher, though the strength remains the same.