Early-age Thermal Crack Control In Concrete Ciria C660 [best] 🆕 Best

Before C660 (published in 2013, superseding the legendary CIRIA C91), thermal control was often reduced to a single mantra: keep the peak temperature below 70°C . But that misses the real enemy: (ΔT) between the hot core and the cooler edge.

Limit pour sizes, decrease the rate of placement, or cast in shorter bays. early-age thermal crack control in concrete ciria c660

Older specifications said "never exceed 70°C core temperature" to avoid delayed ettringite formation (DEF). C660 clarifies: For modern cements with <0.6% alkali content, DEF risk is negligible up to 85-90°C. The real limit is the ΔT (differential), not the absolute peak. Before C660 (published in 2013, superseding the legendary

High external restraint from rock foundation. High cement content (400 kg/m³ CEM I) for early strength. High external restraint from rock foundation

If predicted ΔT > ΔT_allow → Cracking risk is unacceptable. Mitigation measures required.