Crack control in reinforced concrete slabs using polymer grids

The research work presented in this thesis was designed to provide an understanding of the short and long term cracking behaviour of concrete slabs reinforced with Tensar polymer grids.The objectives of the short term test program were to study the effectiveness of polymer grids in controlling the cracks in concrete slabs due to restrained shrinkage. The experimental program included testing of ten large scale rectangular concrete slabs 120 x 600 x 2000 mm in size under controlled humidity and temperature. Test results showed that the use of polymer grids in concrete slabs have practically eliminated any cracks due to shrinkage.The objectives of the long term test program were to study the effectiveness of polymer grids in controlling the cracks in concrete slabs as well as the effect of the control of cracks on corrosion, stiffness and ultimate strength of such slabs. The experimental program included testing of four large scale rectangular concrete slabs 100 x 500 x 3200 mm in size subjected to severe conditions of loading and unloading, wetting and drying, and to deicing salt applications. Test results showed that the use of polymer grids as a secondary reinforcement in concrete slabs significantly reduce cracks width. The maximum crack width was reduced by 30%. The loading test results after nearly 3 years of salt exposure showed an increase of the ultimate strength of 8% and a significant increase (up to 63%) in the initial stiffness.