Modelling the loss in strength of AR-glass fibres in textile-reinforced concrete

Abstract

AR-glass-reinforcement in concrete, which for example is used in the new composite material textile-reinforced concrete, loses strength in the long term as a consequence of weathering. The knowledge of this time-dependant development of strength loss is an essential aspect for the application of textile-reinforced components in structurally relevant areas. The present work describes investigations about the development of strength loss of AR-glass-reinforcement in concrete caused by weathering. First of all, the main reason for the loss in strength of AR-glass in concrete was determined [1]. Based on this, a mathematical approach to describe the loss in strength was derived for constant climatic conditions. This model was verified with numerous test results acquired by various investigation methods. The influence of humidity, temperature, pH-value and glass composition on the loss in strength of the AR-glass-reinforcement was investigated. The loss in strength of the reinforcement starts above a critical humidity and increases exponentially with higher temperatures. Additionally combined loads were analysed to finally derive a basis for a durability-model which can take arbitrarily complex weathering into account. Pull-out investigations underline that the bond between AR-glass-reinforcement and matrix is independent of the long-term weathering.