Fire Performance of Hollow-Core Concrete Slabs with and Without Joint Mortar

EasyChair Preprint 15753

Abstract

Hollow-core concrete slabs have been widely used in the construction industry. However, these slabs may lose their flexural capacities under fire due to the increasing temperatures, leading to a premature failure compared with the fire resistance period specified in the building regulations. This research investigates the use of joint mortar in providing axial restraint to enhance the fire performance of hollow-core concrete slabs. An experimental study is conducted through full-scale fire testing of precast hollow-core concrete slabs having a thickness of 120 mm, with and without mortar being filled in the 100 mm gaps at both ends. The water-to-cement ratio of the mortar is selected as 0.5 to align with that typically used in practice. The results show that the joint mortar is able to induce axial restraint to a certain degree, as evidenced by the reduced thermal expansion of the slabs. However, the increase in the fire resistance capacity of the slabs—as measured by the time to failure—under the specified loading level of 0.3 is marginal and deemed insufficient according to the current building regulations on fire safety.

Keyphrases: Axial restraint, Hollow-core concrete slabs, Joint mortar, fire resistance

@booklet{EasyChair:15753,
  author    = {Parinya Apipunyawong and Thanyawat Pothisiri and Sirichai Pethrung},
  title     = {Fire Performance of Hollow-Core Concrete Slabs with and Without Joint Mortar},
  howpublished = {EasyChair Preprint 15753},
  year      = {EasyChair, 2025}}