Durability of FRC-Materials

Abstract

Asbestos cement was the first type of FRC-material that was ever made. It consisted of neat, hardened Portland cement reinforced with asbestos fibres (Vt - 7 vol-%). The most outstanding and valuable property of a high quality asbestos cement was the highly improved durability of this composite material in comparison to what would have been the case, if no fibres had been added or the fibre reinforcement of this extremely brittle matrix had been carried out incorrectly.This paper describes an analysis of the variation in time of the fracture energy, GF, of different types of FRC-material exposed to various climatic conditions.The following types of fibres were examined: steel fibre, ar-glass fibre, synthetic fibre (polypropylene) and natural fibre (sisal fibre and paper pulp cellulose).The climatic exposure conditions were natural out-door weathering or laboratory tests in a special weather-o-meter. Three test series were carried out at the Danish Building Research Institute. The results from these tests have been compared to results from five test series taken from the literature (ar-glass-, steel-, polypropylen-, sisal-fibres and neat concrete).It is concluded that natural and glass fibres are losing strength and ductility in a cementitious matrix. This results in a drastically reduced fracture energy of the composite material over the years. In the worst cases practically no fibre effect is left after some ten years of normal out-door exposure.For the best types of fibres examined (steel fibre, high tenacity, high bond polypropylene and combinations of these two types) the ductility and fracture energy of the composites are increasing significantly even after very long time of exposure.

A Review of Fiber Synergy in Hybrid Fiber Reinforced Concrete

“…The prominent improvement was noticed because of the addition of steel fibres while enhanced toughness was noticed because of carbon fibre. In another study (Larsen & Krenchel, 1991) steel and propylene fibre were added to the cementitious composite which led to increase in fracture energy by approximately 40% after 10 years of outdoor exposure. Increase in compressive strength due to hybridization of steel and polypropylene fibre is also reported (Mette & Aarre, 1990).…”

Polypropylene fiber–matrix bonds in cementitious composites

“…(1, 2, 3) Individual ow controllers;(7) Pyrex glass reactor;(4, 10) vacuum-tightconnections;(5,9) stainless-steelrings; (6) semi-cylindricalcopper electrodes; (8) RF power supply, 1000 W, 13.56 MHz; (11) valve;(12,13) digitally speed-controlled electric engine transmission system.…”

Axial-flexural interaction diagram of RPC columns reinforced with steel fibres

“…It was reported that the inclusion of steel fibres and polypropylene fibres effectively enhanced the tensile strength, maximum strain and flexural behaviour of the concrete. The improvement was attributed to the role of steel fibre in enhancing the strength and to the role of polypropylene in enhancing the ductility of the concrete [21][22][23]. Moreover, the hybridization of two types of fibre that differ in the modulus of elasticity was reported by Banthia and Sheng [24].…”