The following figure from the above paper shows Trends (in degrees Celsius per 100 years) for each 5 by 5 latitude-longitude grid box using only nonurban stations for annual maximum temperature, annual minimum temperature, and diurnal temperature range for the period 1950 to 1993.
Concrete continues to gain strength after pouring for as long as it retains moisture, but the longer it moist-cures, the slower the rate of strength gain. Moist-curing concrete for 20 days more than doubles its strength compared with four days of moist-curing, which is considered a minimum.oncrete continues to gain strength after pouring for as long as it retains moisture, but the longer it moist-cures, the slower the rate of strength gain. Moist-curing concrete for 20 days more than doubles its strength compared with four days of moist-curing, which is considered a minimum.
It is concrete that is strong enough to carry a compressive stress of 3,000 psi at 28 days. Concrete may be specified at other strengths as well. Conventional concrete has strengths of 7,000 psi or less; concrete with strengths between 7,000 and 14,500 psi is considered high-strength concrete.