A Critical Review of Full-Scale Fire Tests and Prediction Methods for Timber–Concrete Composite Slab Floors

Abstract

Abstract With growing demand on low-carbon and fire-safe building solutions, timber–concrete composite (TCC) floors have emerged as a sustainable and efficient alternative. This paper provides a critical review of the fire performance of slab-type TCC floors, with an emphasis on studies reported in the past five years, including 25 full-scale furnace tests. Results show that cross laminated timber (CLT) concrete floors are prone to char fall-off, leading to sharp inner temperature rises and highly variable fire resistance (30–214 min), mainly influenced by load ratio, lamella thickness, and connection type. The fire resistance of slabs generally exceeded 90 min under service loads, and higher load ratios caused earlier failure. By contrast, nail-laminated timber– and laminated veneer lumber–concrete systems exhibited stable charring and consistently higher resistance ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="greater than 190 min" display="inline" overflow="scroll"> <mml:mo form="prefix">&gt;</mml:mo> <mml:mn>190</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>min</mml:mi> </mml:math> ). Emerging simulation approaches that model char fall-off and temperature-dependent connector degradation show improved agreement during extended fires, though broader validation is still needed. Simplified analytical methods, such as the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="gamma" display="inline" overflow="scroll"> <mml:mi>γ</mml:mi> </mml:math> -method, provide useful estimates but require calibration across load levels. Future research should refine delamination modeling, incorporate temperature-dependent connector behavior, and recalibrate analytical methods using full-scale data to ensure reliable fire design of TCC floors.