Teresa Zych

The paper presents the properties of new generation cementitious composites with fibres, such as “bendable concrete” (ECC, Engineered Cementitious Composites) (plastic, not brittle but resistant to cracking material) with the addition of polyvinyl alcohol (PVA) fibres, high performance concrete (HPC) with glass fibres, reactive powder concrete (RPC) (characterized by ultra-high compressive strength, above 200 MPa) with short steel fibres. The detailed characteristics of the composition of the cement matrix and the role of fibres in the formation of the composite properties are described. Various applications of the composites as structural and architectural materials are also given.

This paper presents the manufacturing and properties of three types of polyolefin fibres: monofilament and fibrillated polypropylene microfibres and macro-synthetic (PP/PE) fibres – today, besides steel and glass fibres, these are the most widely used fibrous reinforcement of cement composites. Different types of fibres result from various methods of improving the low modulus of elasticity and poor adhesion of PP fibres (chemically inert) to the cement matrix. These methods are also described in the paper.

The experimental methods for determination of concrete resistance to chlorides – both the chloride permeability test methods (NT Build 492 NordTest – Non-S teady State Migration Test, AAS HTO T 277-AS TM C 1202 Test) and the methods for testing concrete resistance to surface scaling due to cyclic freezing and thawing in the presence of NaCl solution (deicing salts, saline sea water, etc.) (e.g. Slab Test according to CEN /TS 12390-9, based on the Borås method according to Swedish Standard SS 13 72 44) are presented in the paper. The R apid Chloride Test – the method used “in situ” to determine the chloride ion content in concrete is also described.