Q. Relation of pouring rate and temperature with concrete pressure on formwork

Freshly placed concrete exerts pressure on formwork at the time of the placing operation. It's influenced by the rate of placing and air temperature. For illustration if concrete pouring rate is too slow, setting of concrete starts to occur. Consequently concrete at the bottom of formwork sets prior to the placing of fresh concrete at the top and maximum pressure will be decreased. 

Temperature affects the rate of hydration of concrete. The higher the air temperature is, the higher would be the rate of hydration reaction. Therefore fresh concrete leads to set at a faster rate. Pressure exerted on formwork reduces with an increase in temperature. Therefore formwork is subjected to a higher pressure exerted by fresh concrete in winter than in summer.

Fig: Diagram of design concrete pressure diagram on formwork