BOND BEHAVIOR OF LIGHTWEIGHT FOAMED REINFORCED CONCRETE

Abstract

ABSTRACT The lightweight foamed concrete (LWFC) applications in the structural building are very restricted due to its low strength and brittleness. The experimental work of this study includes two parts: the first involves improving the LWFC as structural material using additives and fibers. Where many trial mixes were made based on the density and design compressive strength. Then, the mechanical properties of the ideal mixture (1800kg/m3, 40MPa) are covered in detail for their effect on the bonding behavior of LWFC. The test results showed that the addition of the fibers into the LWFC mix decreases the flowability by 16.67%, and the other mechanical properties [compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity] are enhanced by 20%, 90.79%, 130.55%, and 113.36% respectively. The second part of this work is the investigation of bond behavior of (Lightweight foamed, Normal) concrete using (GFRP) bars and conventional deformed steel bars. This part includes 54 specimens of the concrete cube with different dimensions (dimensions=10 ). The main variables considered are the concrete type (LWFC, NWC), reinforcement type (GFRP bars, Steel bars), embedded length ratios (3 , 4 , and 5 ) and bar diameters ( 10, 12, and 16). And, when comparing between the two types of reinforcing bars it was noted that the diameter 12 of GFRP bars gives better results as the bond strength ranged (82%-92%) of the bond strength of steel II bars depending while the comparison between the two types of concrete showed that the efficiency of LWFC towards the bond strength is very good and close to the bond strength of NWC and it also surpasses it when using diameter 12 regardless of the relatives' embedded lengths, using the shorter embedded lengths ratios of diameter 10 and embedded length ratio of diameter . Also, all specimens of foamed concrete failed by pull out and the cracks were less and narrower compared to normal concrete. Equations with a high correlation coefficient were derived to represent the laboratory results of a pullout test of LWFC for the two types of reinforcing bars.