NOTCH-SENSITIVITY OF FIBROUS MORTAR BEAMS SUBJECTED TO FLEXURE

للكاتبين

Abdelaty, M. A. Ghazy, M. F. and Showaib, E. A.

Faculty of Engineering, Tanta University

ABSTRACT

In this paper, the effect of notch-size on the behavior of fibrous mortar beams in flexure is

experimentally investigated. Two types of fibers namely glass fibers and polypropylene fibers

are conducted. Identical single edge notched beams cast with glass fibers and polypropylene

fibers were prepared for testing. In addition, identical single edge notched beams cast with

plain mortar were prepared also and tested as reference specimens. A data acquisition system

capable of performing one thousand loops per second was used to continuously record load

and central deflection up till failure. The results were statistically analyzed from which the

notch- sensitivity effect on flexural strength, fracture toughness, fracture energy and

toughness were clearly determined. A decrease in the net flexural strength with the increase of

notch length was noticed only for short notches of plain mortar as well as for mixes

containing 1 % polypropylene fibers type. An increase on the net flexural strength was

recorded for higher notch lengths and for higher polypropylene fibers volume fraction. For

mixes containing glass fibers, an increase of the measured flexural strength was recorded at

all notch lengths.

For plain mortar mix, the fracture toughness KIC values were notch sensitive since the higher

the notch length the higher the fracture toughness values. Mixes containing fibers generally

were less notch sensitive materials although the slightly increase of the measured values at

higher notches.

The results of the fracture energy values indicated that the fracture energy was a notch

sensitive property for the investigated mixes. Moreover, toughness indices values of fibrous

mortar mixes were notch sensitive. The sensitivity degree depends on fiber type rather than

fiber volume fraction. Generally, the results indicated that notch size was found to be

significant of the evaluated properties

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