Applying CIRIA 108, they measured the setting time (E) of the site mix (a high-density concrete with PFA) at 3.5 hours and controlled the rate of rise (R) to 1.2 m/hour. The resulting P_max was just 120 kN/m².
Research (including later CIRIA updates) shows that for SCC, the coefficient (1.2) is insufficient. SCC can maintain fluid-like behavior for longer, leading to near-hydrostatic pressures. ciria report 108 concrete pressure on formwork
Published by the Construction Industry Research and Information Association (CIRIA), Report 108 fundamentally changed how the industry calculates the lateral pressure exerted by fresh concrete. Even with the advent of Self-Compacting Concrete (SCC) and modern admixtures, the principles laid out in this 1985 report remain the industry benchmark. Applying CIRIA 108, they measured the setting time
The report revolutionized formwork design, allowing for lighter, faster, and more economical systems—without sacrificing safety. To understand CIRIA 108, you must abandon the "liquid assumption." SCC can maintain fluid-like behavior for longer, leading
ACI 347 uses empirical curves based on column size. CIRIA 108 is more scientific for walls and unusual geometries because it explicitly accounts for the concrete's hydration chemistry. For complex projects, many engineers run both and use the higher (safer) value. Special Cases: Self-Compacting Concrete (SCC) Standard CIRIA 108 was written before SCC became ubiquitous. SCC has much higher flowability and longer setting retention. Does CIRIA 108 still apply?