LAUSR

Avoiding the formation of shrinkage cracks is one of the most important tasks in construction of concrete industrial floors. Cracks appear on the surface of floors when the nonlinear processes in the structure lead to internal stresses that exceed the actual tensile strength of the concrete. The tensile stresses developed depend on the constrained deformation of the floor during shrinkage and the elastic modulus of the material of the concrete slab. However, on the top surface of the floor, the tensile stresses can be increased, if the shrinkage deformations are constrained by the uneven evaporation and the generated friction between the sub-base and the floor. The value of friction coefficient is depended primarily on the surface roughness of the subbase and the type of polyethylene foil used between the sub-base and the concrete slab. The paper presents the results of experimental investigations on the friction coefficient and the effects of its value on the cracking process of industrial concrete floor...