Studies indicate that for certain low-friction formwork, the CIRIA arching criterion (which assumes pressure stops increasing after a certain point) might be less conservative than ACI recommendations.
The speed at which the vertical level of concrete rises. ciria report 108 concrete pressure on formwork
As cement hydrates, the concrete loses workability and begins to stiffen. This chemical transformation matrix limits how much hydrostatic pressure can build up over time. Temperature of the Mix Studies indicate that for certain low-friction formwork, the
Pmax=D⋅[C1⋅R+C2⋅K⋅Hi−C1⋅R]cap P sub m a x end-sub equals cap D center dot open bracket cap C sub 1 center dot the square root of cap R end-root plus cap C sub 2 center dot cap K center dot the square root of cap H sub i minus cap C sub 1 center dot the square root of cap R end-root end-root close bracket Characteristic Stiffening Time (
): Measured in degrees Celsius at the time of placing. Lower temperatures delay the chemical hydration process, causing the concrete to remain fluid longer and exert higher pressure. Characteristic Stiffening Time (
Studies indicate that for certain low-friction formwork, the CIRIA arching criterion (which assumes pressure stops increasing after a certain point) might be less conservative than ACI recommendations.
The speed at which the vertical level of concrete rises.
As cement hydrates, the concrete loses workability and begins to stiffen. This chemical transformation matrix limits how much hydrostatic pressure can build up over time. Temperature of the Mix
Pmax=D⋅[C1⋅R+C2⋅K⋅Hi−C1⋅R]cap P sub m a x end-sub equals cap D center dot open bracket cap C sub 1 center dot the square root of cap R end-root plus cap C sub 2 center dot cap K center dot the square root of cap H sub i minus cap C sub 1 center dot the square root of cap R end-root end-root close bracket
): Measured in degrees Celsius at the time of placing. Lower temperatures delay the chemical hydration process, causing the concrete to remain fluid longer and exert higher pressure. Characteristic Stiffening Time (