Title: Practical Experiences on Cracking of Concrete Slabs on Ground

Author(s): Jukka Lahdensivu, Jari Hietala, Kari Saastamoinen,

Publication: NCR

Volume: 40

Issue: 2

Appears on pages(s): 11-20

Keywords: concrete floor, slab on ground, cracking, shrinkage

DOI:

Date: 12/15/2009

Abstract:
Concrete ground floor slabs are commonly used floor type in Finland. According to Finnish Guide for Concrete Floors (by 45) concrete slab on grade can be made with centric reinforcement if slab thickness is varied between 80 – 120 mm. A survey about industrial and warehouse floors showed that extensive surface cracking was found very often in the slabs with centric reinforcement. In many cases cracks were so wide that they reach the reinforcement in the neutral axis or in some cases cracks reach the bottom surface of slab. Cracking can seriously reduce esthetical value of floor, but also long-term durability of reinforcement can be decreased due to the possible chemical attack through cracks and because the surface coating is broken. Cause for cracking is due to the differential shrinkage when the top of the slab dries faster than the bottom of the slab.