Curling of Concrete Floor Slabs on Grade — Causes and Repairs

Abstract

Many industrial floors are required to have high-quality flat surfaces for the operation of specialized equipment, particularly high-reach stackers operating from the surfaces of warehouse floors. For new floors, the essence of floor flatness lies in the manner of finishing and the systematic monitoring of the flatness achieved immediately following construction. Achieving such surfaces in floor slabs however, is quite difficult because of the moisture and temperature gradients that cause them to curl at the joints. Such curling seriously affects the operation of an industrial facility. Floors subjected to heavily loaded forklift traffic may rapidly deteriorate, causing safety problems. Curling is also exacerbated in industrial floors by the use of power-troweled surface hardeners to produce the dense high-strength top surface required for high wear resistance. Repair of curled floors in industrial locations involves grinding, patching, installation of dowels, and grouting underneath the curled slab. The timing and appropriateness of the method used are of vital importance to the durability of the repair. Aspects of design and construction to minimize curling of new industrial floors, the factors that contribute to cracking and curling, measures to minimize curling, and the repair of curled floors are discussed in this paper.