Within the last decade, a new class of civil engineering materials referred to as High Performance Fibre Reinforced Cementitious Composites (HPFRCC) has been developed. As a subset in this new field, additions of polypropylene (PP) fibres, in the form of woven textile fabrics, have proved most successful as reinforcement to cementitious matrices, leading to the development of a novel composite material: so called “Textile Concrete” (TC). Although the strength and modulus of PP are not very high, careful design through the appropriate placement and high fibre volume fraction of a textile format, has led to sufficient strength, stiffness, and high toughness. In particular the development of a fibrillated core fibre to which is attached an outer layer of ultrasonically welded, or bonded “fluffy” PP fibres, has been most successful, and is a unique feature. These outer fluffy layers provide excellent physical bonding characteristics to the cement matrix, thus overcoming the intrinsic hydrophobic nature and otherwise weak matrix bonding of PP fibres. This book deals with the effects of ageing on the mechanical performance of TC.