Flexural performance of functionally graded RC cross-section with steel and PP fibres

Abstract

Many studies have been conducted on the behaviour of reinforced concrete (RC) to determine the effects of different fibre types on the mechanical properties of concrete. Tests such as flexural and shear tests are used to evaluate the behaviour of RC. Most previous studies have focused on reinforcement of the entire cross-section with one fibre type, but the use of double-type reinforcement is growing and the lower cost of polypropylene (PP) fibres can be a significant factor in the use of double-type reinforcement. Therefore, in this work, experimental tests and numerical simulations were carried out to study reinforcement of the cross-section with steel fibres, PP fibres or both, in two separate layers. Beams were reinforced using 0 . 5%, 1% and 2% fibre volume fractions of steel and PP fibres. The beams with a reinforced cross-section with one or two fibre types were evaluated under flexural loading. The results showed that reinforcement of the entire cross-section with steel fibres led to a higher load-carrying capacity than reinforcement of the cross-section with two fibre types in two separate layers.

Performance of Two-way RC Slabs Retrofitted by Different Configurations of High Performance Fibre Reinforced Cementitous Composite Strips

“…According to Naghibdehi and Sharbatdar [17] an HPFRCC mix which exhibits a very ductile with a relatively high tensile strength in its hardened state was chosen for experimental tests in this paper. A volume fraction of 2% hookended steel fibres with the ratio of length to diameter (L/D) equal to 47.62 (50 mm long and 1.05 mm diameter) was used, (Fig.…”

“…During these years, many investigations on the use of HPFRCC material have focused on the effects of bonding conditions between the substrate concrete and the HPFRCC [15], the layer thickness [16], fibre volume fraction and properties of the HPFRCC mix [17], the crack growth and propagation [18], optimization and flexural performance [19,20] and tensile strain-hardening behaviour [21]. Recently, the feasibility of using HPFRCC for the rehabilitation and strengthening of deficient or damaged RC members has investigated widely [16, 22 -29].…”

Ponašanje slojevito mikroarmiranih betonskih greda izloženih cikličkom opterećenju

“…s 2 % čeličnih vlakana. Kod greda s dva sloja, najbolja svojstva su postignuta u uzorku s 1 % čeličnih vlakana [12,13]. Rezultati prijašnjih ispitivanja te metode armiranja dobiveni su na osnovi ispitivanja greda pod utjecajem jednolikog opterećenja, ali takvo ispitivanje nije provedeno za ciklička opterećenja.…”

“…Ghasemi Naghibdei i suradnici pokazali su da učinkovitost ojačanja, primjenom metode slojevitog ojačanja betona vlaknima (slojevito mikroarmiranje), značajno ovisi o vrsti vlakana, njihovoj količini i rasporedu slojeva [12,13]. Ojačanjem betona na taj način omogućen je odabir rasporeda slojeva, vrste vlakana, veličina frakcije s obzirom na primjenu betona.…”

“…Da bi se procijenilo ponašanje greda prilikom savijanja, ispitano je 13 greda dimenzija 100×100×400 mm pod utjecajem koncentrirane sile u sredini raspona, pri brzini od 0,5 mm/min. Prema prethodnim istraživanjima [13], veći broj slojeva manje debljine u gredi utječe na povećanje otpornosti na savijanje. Manja debljina slojeva betona omogućuje da se vlakna ravnomjerno raspodijele u betonskom sloju.…”