Influence of cement type and mixing pressure on air content, rheology and mechanical properties of UHPC

Effect of Fiber Hybridization on Durability Related Properties of Ultra-High Performance Concrete

“…Less workable concrete contains more entrapped air which cannot escape from the mass because of the high viscosity of the mixture. Poor workability leads to a higher content of air in the cavities and pores of the capillaries which have an important impact on the mechanical properties and the durability properties of the concrete (Dils et al 2013). When the capillary porosity decreases, a small amount of water is absorbed and saturation does not occur so easily.…”

“…When the capillary porosity decreases, a small amount of water is absorbed and saturation does not occur so easily. This gives a higher resistance to freeze-thaw cycles, and penetration of chlorides and sulphates (Dils et al 2013;Aïtcin 2003). The mean values of UHPC properties shown in Table 3 are based on papers (Smarzewski and Barnat-Hunek 2015;Barnat-Hunek and Smarzewski 2016).…”

Corrosion of Glass Fibres in Ultra High Performance Concrete and Normal Strength Concrete

“…Another advantage of UHPC reinforced with glass fibres are its aesthetic properties (thinner and lighter structures), which is important e.g. for architectural elements [2][3][4][5][6][7][8][9][10][11]. Rigaud in his study [10] showed that the ideal content of glass fibres is ca.…”

“…UHPC concrete, thanks to the higher micronization and higher purity of the employed materials, features high compactness, very low porosity and even reduced alkalinity of the pore solution [1][2][3][4][5][6][7][8][9][10][11]. After the setting the glass fibres and the UHPC concrete matrix did not demonstrate such chemical changes as it was the case with NSC concrete, in which, due to its character and structure, the pore solution can be transported also after hardening of the samples and thus also the concrete matrix changes its chemical composition.…”

“…The most recognized parameter for definition of UHPC is compression strength, which shall be at least 150 MPa and which significantly exceeds the highest strength class C100/115, as defined in ČSN EN 206-1/Z3 [2]. However, in practice the compression strength may be up to 250 MPa [3] and under laboratory conditions it can be over 400 MPa. The minimum tensile strength is 7 MPa [4], however, its usual value is over 15 MPa [2].…”