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Abstract: In 2001, a multi-phase research program was started at the American University of Beirut (AUB) to evaluate the effect of steel galvanizing on bond strength of reinforcement in concrete structures. This paper reports on the fourth phase of the program designed to assess the effect of steel galvanizing on bond strength of hooked bars anchored in high strength concrete structures. Twelve specimens, each simulating the rigid connection of two cantilever beams to a column, were tested. The variables included bar size and the confinement mode of the beam bars anchored in the column. Test results indicated that galvanizing caused a consistent reduction in bond strength of hooked bars ranging from 6% to 17% with an average of 13%. This is contrary to the results of the earlier phase of the AUB program which indicated strength concrete structures. Based on analysis of test results of all four phases of the AUB research program, design recommendations insignificant effect of steel galvanizing on bond strength of hooked bars anchored in normal are provided concerning the anchorage length of galvanized reinforcing bars in normal and high strength concrete structures. [Copyright &y& Elsevier]

Abstract: In 2001, a multi-phase research program was started at the American University of Beirut (AUB) to evaluate experimentally the effect of hot dip galvanizing on bond strength of reinforcement in concrete structures. In the first two phases, 24 full-scale beam specimens were tested in positive bending to evaluate the effect of galvanizing on bond strength of tension lap splices in normal and high strength concrete specimens. The variables were bar size, concrete strength, the amount of transverse reinforcement confining the splice region, and whether the bars were galvanized or not. Test results indicated that galvanizing had a negligible effect on bond strength of reinforcement in normal strength concrete. However, galvanizing caused an average of 20% decrease in bond strength of reinforcement in high strength concrete regardless of the amount of transverse reinforcement confining the splice region. This paper reports on a third phase of the AUB program, designed to evaluate the effect of galvanizing on anchorage performance of hooked bars in normal strength concrete structures. Up to date there has been no research work done in this area. Twelve specimens were tested. The specimen simulated the rigid connection of two cantilever beams to a column. The variables were bar size, the confinement mode of the beam bars anchored in the column, and whether the bars were galvanized or not. The effect of galvanizing was evaluated by comparing the performance of galvanized bars with black bars based on the mode of failure, ultimate load, and the general load–deflection behavior. Test results indicated that effect of galvanizing on the bond strength of hooked bars in normal strength concrete was not significant. [Copyright &y& Elsevier]

Abstract: Hot-dip galvanizing is one of the methods used to solve the problem of corrosion of reinforcement in concrete structures. The few research reported in the literature on the effect of galvanizing on bond strength of reinforcing bars anchored in pullout specimens, indicates contradictory results. The primary objective of this paper is to evaluate experimentally the effect of hot dip galvanizing on the bond capacity of tension lap splices. The test results may have an implication on the development length and splice length design provisions of galvanized bars in building design codes. To achieve the objective, six concrete beam specimens were tested in positive bending. For each of three bar sizes 20, 25, and 32 mm, two companion beams identical except for whether the bars were black or galvanized, were tested. Each beam was designed with bars spliced at midspan in a constant moment region. The nominal concrete strength was 28 MPa. The mode of failure was splitting of the concrete cover in the splice region. The test results indicated that the use of galvanized bars has a negligible negative effect on bond strength of reinforcement in normal strength concrete. [Copyright &y& Elsevier]

There is a current trend all over the world to investigate the utilization of processed and unprocessed industrial by-products and domestic wastes as raw materials in cement and concrete. This has a positive environmental impact due to the ever-increasing cost of waste disposal and stricter environmental regulations. Historically, reference books on concrete technology and cement chemistry indicate that the leakage of oil into the cement in older grinding units resulted in concrete with greater resistance to freezing and thawing. This effect is similar to adding an air-entraining chemical admixture to the concrete. Such information is not backed by any research study reported in the literature. The objective of the research reported in this paper was to investigate the effects of used engine oil on properties of fresh and hardened concrete. The main variables included the type and dosage of an air-entraining agent (commercial type, used engine oil, or new engine oil), mixing time, and the water/cement ratio of the concrete. Results showed that used engine oil increased the slump and percentage of entrained air of the fresh concrete mix, and did not adversely affect the strength properties of hardened concrete. [Copyright &y& Elsevier]

This paper reports on the second phase of a research program started at the American University of Beirut (AUB) to study the effects of used engine oil on concrete properties and concrete behavior. In the first phase, the effect of used engine oil on properties of fresh and hardened concrete was investigated. Results indicated that used engine oil acted as an air-entraining agent by improving the slump and fluidity of the concrete mix, and enhancing the air content of fresh concrete. Reductions in the strength properties of hardened concrete due to the incorporation of oil were not as significant as when a commercial chemical air-entraining admixture was used. Results of the first phase of the AUB study instigated further investigation reported in this paper. The objective was to evaluate the effect of used engine oil on structural behavior of reinforced concrete elements. Six full-scale beam specimens were tested in three sets. The difference between the three sets was the mode of failure of the beams: flexure; shear; or bond. The two companion beams in each set were identical except for the use of engine oil in one of them. The beams were tested in positive bending. Results showed that regardless of the mode of failure, used engine oil did not have any significant effect on the ultimate load or load-deflection behavior of the beams. [Copyright &y& Elsevier]

Highlights: [•] Mixes with finer aggregate gradation and soft asphalt binder showed better fatigue performance. [•] The range of slope coefficient (K2), obtained from fatigue equation is from 2.03 to 4.25. [•] A reasonable relationship exits between the slope and intercept coefficient of fatigue equation. [•] Stone dust as filler improves the fatigue performance of asphalt mix. [Copyright &y& Elsevier]