توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱APPLICATION OF FIBER REINFORCED PLASTICS FOR CONCRETE T–BEAM BRIDGE STRENGTHENING
نویسنده(ها): ، ،
اطلاعات انتشار: سومین کنفرانس بین المللی بتن و توسعه، سال
تعداد صفحات: ۶
A strengthening method using fiber reinforced plastics (FRP) has been widely applied for deteriorated reinforced concrete bridges. Advantages of this method may include that the strengthened structures do not increase dead weight and that no corrosion is concerned. From various experimental studies, behavior characteristics of the FRP strengthened structural members have been generally well evaluated. The majority of those studies, however, have been performed on laboratory sized structural members rather than actual full scale bridges. The study herein used a full scale actual deteriorated bridge to evaluate the strengthening effects with three different FRP materials, carbon fiber sheet, glass fiber reinforced plastics and aramid fiber sheet. In the field load tests, concrete weight blocks were
used as a loading system instead of commonly used a live–truck load or hydraulic jacking force. The strengthening was designed as specified in ACI 440.1R which is based on the ultimate strength design concept. From the measured behaviors, it was confirmed that the strengthening using FRP materials successfully improved the flexural capacity of the aged and deteriorated concrete bridge. The strengthened girders behaved linearly up to the design moment even though the applied stress distribution mechanisms were different depending on the FRP materials. Therefore, it is concluded that the strengthening design method specified in ACI 440.1R can be successfully used for actual full scale bridges strengthened with external FRP bonding.<\div>

۲APPLICATION OF HYBRID FIBER REINFORCEMENT AND HIGH VOLUME COARSE FLY ASH IN SELF COMPACTING CONCRETE
نویسنده(ها): ، ،
اطلاعات انتشار: سومین کنفرانس بین المللی بتن و توسعه، سال
تعداد صفحات: ۱۱
Self compacting concrete is termed as a concrete with high flow ability and cohesiveness which can fill its mold without the need of any extra vibration effort. Fiber inclusion to concrete enhances the mechanical properties, while making the concrete less workable. This article presents a study on the fresh and mechanical properties of a fiber reinforced self compacting concrete incorporating highvolume
fly ash that does not meet the fineness requirements of ASTM C 618. A poly carboxylic based superplasticizer was used in combination with a viscosity modifying admixture. In mixes containing fly ash, 50% of cement by weight was replaced with fly ash. Two different types of steel fibers were used in combination, keeping the total fiber content constant at 60 kg\m3. Slump flow time and diameter, V funnel, and air content were performed to assess the fresh properties of the concrete. Compressive strength, split tensile strength, and ultrasonic pulse velocity of the concrete were determined for the hardened properties. It can be concluded that high–volume coarse fly ash could successfully be used in producing fiber reinforced SCC. Even though there is some reduction in the concrete strength, because of the use of high–volume coarse fly ash, it is possible to achieve self compaction with considerable fiber inclusion.<\div>

۳WASTE CEMENT AND CONCRETE MANAGEMENT AS COSTEFFECTIVE AND ENVIRONMENT FRIENDLY: PRINCIPLES AND PERSPECTIVES
اطلاعات انتشار: سومین کنفرانس بین المللی بتن و توسعه، سال
تعداد صفحات: ۱۱
The use of recycled aggregates in concrete opens a whole new range of possibilities in the reuse of materials in the building industry. The utilization of recycled aggregates is a good solution to the problem of an excess of waste material, provided that the desired final product quality is reached. The studies on the use of recycled aggregates have been going on for 50 years. In fact, none of the results showed that recycled aggregates are unsuitable for structural use. Using the recycled aggregate is a cost–affective and environmental friendly solution which is required general waste concrete management knowledge. This paper is focusing on waste cement and concrete management for optimizing the construction costs. The ways for reducing the green house gases (GHG) at cement and batch plants are suggested. A comparison among Iran industrial utilized cement volume and other countries was performed. Finally, it can be concluded that application of recycling concrete could reduce the costs by reducing truck traffic, providing the Non– Renewable Resource, Better Trucking Utilization (Reduced Costs), Allow down to 10% Deleterious Materials in Iran.<\div>
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