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An experimental program was carried out to investigate the behavior of steel, fiber reinforced concrete (SFRC) under abrasion and cycles of freeze and them. Compression and flexural tests were also performed in order to reach a comprehensive conclusion of the response. In total, over 200 specimens were tested The test variables included two concrete strength., (i. e., 28 MPa as Normal Strength (NSFRC) and 42 MPa as Medium Strength (MSFRC)), four volumetric percentage of fibers (i.e., 0%, 0,5%, 1.0% and 1.5%) and two fiber lengths (i.e.. 25mm and 35rnrn).Cube specimens were tested according to ASTM C6661n-ocedrrre B using 100 cycles of freeze and thaw. The Los Angeles test method for testing aggregate was used to evaluate the abrasion resistance of SFRC.Test results of1VSFRCptesertted improvements up to 39% and 32 % in cylindrical and cubic compressive strength, respectively. and 88�o in modulus of rupture, 57% in resistance against abrasion based oil weight loss and 40% against compressive strength reduction due to freeze and thaw cycles. The corresponding improvements for MSFRC were 18%, 16%, 48%, 53% and 46% respectively.Increase in cocncrete strength from 28 Ala to 42 MPa provided higher freeze and thaw and abrasion resistance than addition of 1.5% of steel fibers to the normal strength concrete matrix.

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Results of an experimental investigation performed to evaluate the effect of various concrete strength levels on behavior of lightweight concrete (LWC) under pure torsion are reported.The principle variable of the testing program was compressive strength of concrete (�'c) which ranged between 6.9 and 81.4 MPa. Ten mixture proportions were utilized for LWC of 1500 to 2050 kg/m3 unit weight. In total, sixty four (thirty two pairs) rectangular specimens with 100x 200 mm cross-section were tested. Ultimate torsion strength of LWC increases as uniaxial compressive strength increases however the increase rate reduces for high levels of concrete strengths. The test results are compared with predictions of elastic and plastic theories for torsion and the ACI Code. The Code underestimates the cracking torque of LWC under pure torsion. A regression equation incorporating test results is higher than the ACI equation prediction by a factor of 1.12.

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In this paper the response of cantilevered reinforced concrete (RC) beams with smart rebars under static lateral loading has been numerically studied, using Finite Element Method. The material used in this study is SuperelasticShape Memory Alloys (SE SMAs) which contains nickel and titanium elements. The SE SMA is a unique alloy that has the ability to undergo large deformations and return to their undeformed shape by removal of stresses. In this study, different quantities of steel and smart rebars have been used for reinforcement andthe behavior of these models under lateral loading, including their load-displacement curves, residual displacements, and stiffness, were discussed. During lateral loading, rebars yield or concrete crushes in compression zone in some parts of the beams and also residual deflections are created in the structure. It is found that by using SMA rebars in RC beams, these materials tend to return to the previous state (zero strain), so they reduce the permanent deformations and also in turn create forces known as recovery forces in the structure which lead into closing of concrete cracks in tensile zone. This ability makes special structures to maintain their serviceability even after a strong earthquake