توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱EVALUATION OF THE FLUIDITY AND MECHANICAL PROPERTIES OF LIGHT–WEIGHT SELF–COMPACTING CONCRETE CONTAINING EXPANDED POLYSTYRENE (EPS)
نویسنده(ها): ، ، ،
اطلاعات انتشار: سومین کنفرانس بین المللی بتن و توسعه، سال
تعداد صفحات: ۱۲
This paper presents the results of an experimental investigation on the effects of expanded polystyrene polymeric beads on the properties of light–weight selfcompacting concrete in fresh and hardened states. Since the aim of this study is to produce structural lightweight self–compacting concrete (with compressive strength above 17 MPa), EPS beads were partially substitute for aggregates by 10, 15, 22.5 and 30 percentages by volume. Fluidity and mechanical properties of selfcompacting EPS concrete was compared with ordinary self–compacting concrete with slump flow of about 65cm. The slump flow was kept in allowable range and the effects of EPS were evaluated on the other fluidity parameters such as V–funnel and L–box. The results obtained, showed that with increasing in EPS volume, Vfunnel time increased while blocking ratio decreased. At the stage of hardened concrete, compressive strength (at different ages), tensile strength, ultrasonic pulse velocity (UPV) and water absorption were studied.<\div>

۲An Experimental Comparative Survey on the Interpretation of Concrete Core Strength Results
نویسنده(ها): ، ، ،
اطلاعات انتشار: نخستین کنفرانس بین المللی تکنولوژی بتن، سال
تعداد صفحات: ۹
Estimates of concrete strength are often made from compression tests on cores which have diameter considerably less than the recommended 100 mm. This paper examines the results of tests applied on the 75 and 50 mm diameter cores. A total number of 300 cores were tested. The effects of both specimen sizes and strength levels for different length–todiameter (l\d) ratios of 2, 1.6, 1.4 and 1 on the compressive strength of smaller diameter cores were analyzed. The test results obtained from core specimen were compared with those of standard specimens. The test results showed that the core size had negligible effect on the strength of the cores. The age of the concrete was found to be an effective factor inthe interpretation of the core strength results. Test results also revealed that the l\d ratio of the specimen is more effective for small diameter cores. The coefficient of variation of strength values was noticed to be somewhat higher for 50 mm diameter cores.<\div>

۳Seismic Upgrade of Beam–Column Joints with FRP Plates
نویسنده(ها): ،
اطلاعات انتشار: چهارمین کنفرانس بین المللی مقاوم سازی، سال
تعداد صفحات: ۱۲
Many opportunities are becoming available for using composite materials to strengthen\upgrade existing reinforced concrete (RC) structures. the objective of the rehabilitation is to upgrade the shear strength of these joints andreduce the potential for bond–slip of the bottom bars of the beam. Fiber reinforced polymer (FRP) sheets are wrapped around the joint to prevent the joint shear failure. The FRP plates provide flexural strengthening, whereas the lay–up laminates provide confinement and shear strengthening. Along with the modeling of such upgraded connections to assess the increase of strength and\or ductility provided by the composite reinforcement, an experimental program was planned and it is being undertaken. A preview of it is given in this paper together with an explanation of its philosophy; furthermore, interesting preliminary results are presented and discussed. It appears that the proposed upgrade method will have a significant impact of the engineering practice in the near future<\div>
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