How rapidly concrete is tested affects the value of the modulus of elasticity obtained. If the loading rate is very fast, the concrete may withstand higher than normal stresses. Conversely, if the loading rate is too slow, a much lower value for the modulus of elasticity may result because of the increase in strain in the concrete. Therefore, the modulus of elasticity reported in both of these situations will not be accurate to its true value. When testing concrete cylinders, the loading rate should be between 10 and 100 lb/in²/s.