A 1: 1½ : 3 mix (by mass) has a water/cement ratio of 0.4 and a cement content of (400) kg/m3. The temperatures of the ingredients are as follows: cement 64 ºF, aggregate 86 ºF, and water 68 ºF. Assuming that the aggregate has negligible absorption, calculate the temperature of the fresh concrete. Also calculate how much ice is required to reduce the temperature of the fresh concrete to 61 ºF. Briefly explain why the compressive strength of concrete is its most important property?