Air temperature 23 °C; relative humidity 50%; concrete temperature 30 degC; wind speed 20 km/h

(i) Draw in the following figure and determine rate of water evaporation. Please upload your drawings below.

(ii) The maximum evaporation rate is 1.0 kg/m2/h. What is the maximum wind speed allowed if the other parameters remain unchanged?

(ii) The maximum evaporation rate is 1.0 kg/m2/h. What is the concrete temperature allowed if the other parameters remain unchanged? 

Why does bleeding occur within concrete? Mention three adjustments you would make to the concrete mix proportions to reduce it?

Why compaction is needed for concrete? List at least three types of compaction.

What is plastic shrinkage cracking? Is it detrimental to concrete strength? What are the solutions to plastic shrinkage cracking?

Define workability of concrete and discuss the factors affecting the workability of concrete.