A Study on Properties of Polypropylene Fibre-Mesh

Dr. Jaspal Singh, Department of civil engineering, Punjab Agricultural University, Ludhiana, Punjab.

Introduction

Concrete is widely used constructional material with its high compressive strength. But it has some flaws like shrinkage and cracking, low tensile and flexural strength, poor toughness, high brittleness, low shock resistance etc. To overcome these deficiencies, additional materials are added to improve the performance of concrete. Use of fibres has been developed in recent years. It has been successfully used in construction with its excellent flexural-tensile strength, resistance to splitting, impact resistance, excellent permeability, and frost resistance. It is an effective way to increase toughness, shock resistance, and resistance to plastic shrinkage cracking of the mortar. Cracks in concrete occur due to the nature of the material. Cracks can be of two types, structural and non structural. Non structural cracks are neither harmful to a structure nor to its serviceability. Cracks up to width of 0.3mm are tolerable [5]. But more than 0.3mm width or structural cracks can be harmful for the structure. These cracks can be reduced by adding fibres to concrete.

Fibre mesh is typically polypropylene (plastic) fibre introduced into the mix during the batching process. These fibres serve as a secondary reinforcement in the concrete. The fibre is produced by special technology with polypropylene as a raw material. The products appear net-like structure with many fibre monofilaments connected. When the fibre is put into the concrete, the horizontal structure in fibre monofilament can be destroyed in the course of stirring, owing to friction and rubbing, and the fibre monofilament or net-like structure will fully stretch, thus the concrete is reinforced by a very large number of polypropylene fibres.