BASIC BEHAVIOUR OF NATURAL BANANA STEM FIBER REINFORCED CONCRETE UNDER UNIAXIAL AND BIAXIAL TENSILE STRESS

Abstract

In order to study the basic behavior of natural banana stem fiber reinforced concrete, three typeof tensile strength test namely split tensile strength, flexural strength and biaxial fatigue flexure strength wereconducted. Comparison of these three type of tensile strength, their crack pattern and the way they fails werebe analyzed and discussed. Results showed that the flexural strength value of the two type of biaxial tests arehigher than the uniaxial test result( ASTM C-1550 have 47.046 % higher than ASTM C-78 and 37.871 %higher than ASTM C-496). The value of tensile strength as measured by ASTM C-1550-02 is slightly higherthan the value of the flexural tensile strength as measured by the biaxial flexure test (21.062%). The lines ofthe crack pattern do not show clear macro fracture cracks before reaching the peak load. As observed, there aretwo peak load values found were the one occurred at the first cracked, after that the load stress curve decreasefor a while and after a few seconds the load increase again to a value smaller than the first peak load value.Thisis because at the time of the first cracking in three axes symmetry, the load that can be maintained by theconcrete specimen had reached its maximum but after that the load increase again because the stress has beentransferred to the fiber, so the stress rises again until the fiber break off. This indicates that the fiber plays animportant role in holding and redistributed the tensile load.