|
High performance cementitious composite (HPCC) is a brittle material. Reinforcement of HPCC
with accidentally dispersed _bres can decrease its brittleness, improve ductility as well as resistance to
crack development. These _bres are e_ective in arresting the micro and macro-cracks. Generally, the
_bre reinforced concrete (FRC) in commercial applications include the use of a single type of _bre.
However, one _bre type may be e_ective in a partial range of the crack growing and deformation in
concrete. HPCC with hybrid _bres is a composite that contains di_erent types of _bres, e.g. from a
di_erent material, or other both _bre shape and geometry. In hybrid FRC exists the positive interactions,
usually called synergies, between the di_erent _bre types and causing hybrid performance. Fibre mixtures
can provide synergy in hybrid composites based on the _bre constitutive response, _bre dimensions and
its function. This article presents the results of the HPCC study with three di_erent types of _bres
with eight di_erent _bre volume fractions 0.75%, 1%, 1.25%, 1.5%, 1.75%, 2%, 2.25%, 2.5%. The
designed mixtures use hooked-end steel macro-_bres, crimped polypropylene macro-_bres and straight
glass micro-_bres added respectively in two di_erent proportions 1:1:1 and 1.5:1.25:0.25 to obtain
improved characteristics of hybrid cementitious composites. In order to examine the fresh properties
of HPCC the slump _ow tests were performed. Control and three-_bre HPCC specimens were cast.
Experimental tests of the compressive strength, splitting tensile strength and _exural toughness were
carried out. The test results were widely analyzed to determine the maximum synergy associated with
the variable _bre combinations in terms of _exural toughness and fracture energy.
|
