Abstract: Now a days to ensure sustainability low carbon emission environment friendly products are considered widely around the world. In the construction field, artificial fibres has been researched and used since long time. They are detrimental to the environment due to being non-degradable, non-renewable and high oil consumption. Therefore, there are thoughts to replace them with the natural fibres. In this paper, sisal fibre is considered and are used within 8 mm thick plaster of masonry column. In order to gauge the contribution of sisal fibre within plaster, comparison with unplastered and plain plastered columns are carried out. Two samples of each are considered. The outcome of the experiment revealed that the 8mm thick sisal reinforced plaster column was more ductile and it can be found 1200% and 27% improvement in failure load from unplastered and plain plastered column, respectively, when subjected to out of plane lateral load.
Abstract: Recent studies on compressive and flexural behavior of Wheat Straw Reinforced Concrete (WSRC) showed positive signs for increasing the toughness of concrete. This ultimately will help in reducing the micro-shrinkage cracking in rigid pavements. Splitting-tensile behavior is also an important property which needs to be investigated for WSRC. The overall aim of the research program is the development of economic and durable design for new rigid pavements by using locally available natural fibres in concrete. In this work, splitting-tensile strength of WSRC is investigated experimentally. To study the influence of wheat straw for having concrete with improved properties, Plain Concrete (PC) properties are taken as reference. The proportions of cement, sand and aggregates for PC and WSRC are taken as 1, 2 and 4, respectively. Wheat straw having length of approximately one-inch and contents of 1%, 2%, and 3%, by mass of wet concrete, are used to make WSRC. Water-cement ratios for PC and WSRC are taken as 0.55 and 0.60, respectively. Discussions on splitting-tensile behavior (strength, pre-cracked/cracked energy, and toughness index) of PC and WSRC specimen are made. It is concluded that splitting-tensile toughness index of WSRC is more than that of PC. As results seem favorable, so further study focusing on optimization of materials and durability of WSRC is recommended.
Abstract: This paper presents an experimental study on the compressive behavior of circular concrete columns confined by a new class of composite materials originated from basalt rock, Basalt Fiber Reinforced Polymer (BFRP). The primary objective of this study is to observe the compressive behavior of BFRP-confined cylindrical concrete column specimens under the effect of different number of layers of basalt fiber as a study parameter (3, 6, and 9 layers). For this purpose, 8 small scale circular concrete specimens with no internal steel reinforcement were tested under monotonic axial compression to failure. The results of BFRP-confined concrete specimens of this study showed a bilinear stress-strain response with two ascending branches. Consequently, the performance of confined columns was improved as the number of BFRP layer was increased, in which all the specimens exhibited ductile behavior before failure with significant strength enhancement. The experimental results indicate the well-performing of basalt fiber in improving the concrete compression behavior with an increase in number of FRP layers.
Abstract: Bridge redundancy is defined as the ability of a bridge system to continue to carry load after the failure of one or several structural components. A bridge will collapse progressively after the failure in some main components, if the bridge is in short of redundancy. The system factors for redundancy have been investigated in the design of the bridges with simple systems. However, there is no corresponding redundancy criteria established for the bridges with long span and complicated structural systems. This paper studied the superstructure of a through steel box tied arch bridge. The member failure state, ultimate limit state and functionality limit state were analyzed with ‘Step-by-Step’ procedure. Thus, the most critical component and weakest damaged systems are determined. It is concluded that this through steel box tied arch bridge has enough level of redundancy. This finding could be a reference for the design and maintenance for bridges with similar structural systems.
Abstract: A new low clinker cementing material applying to different concrete strength is developed in this paper. The experiential results show that standard consistency water consumption of the new material is less than the ordinary material; and the particle size is better than the ordinary material. And the cracking performance of the concrete made by the new material is far better than the performance of the concrete made by the ordinary material. Furthermore, the shrinkage of the concrete made by new material is less; and the resistance ability to carbonation is higher. Especially, our proposed new material could make the gel body dense and become six components of concrete into four, which simplifies the production process of concrete mixing station. At the same time, the prepared concrete made by the new material has better construction performance, volume stability and high durability. Unfortunately, the initial and final setting time of the new material are slightly longer. However, the initial and final setting time are still able to meet the national requirements. And most of all the new material meets the requirements of green high performance concrete.
Abstract: The application of hysteretic steel damper for seismic protection and rehabilitation has been recognized efficient and cost effective method in reducing structural responses under seismic events. The damper absorbs seismic energy through its hysteretic behaviour. This study aims to assess the vulnerability of building strengthened with hysteretic steel damper considering variability of stiffness ratio parameter in hysteretic steel damper for the application in six-story steel building. Probabilistic Seismic Demand Model (PSDM) for the structural model is developed by using nonlinear dynamic analysis under 30 ground motions. Furthermore, fragility curves are constructed based on inter-story drift and spectrum acceleration. Finally, the performance of the steel structure with and without hysteretic steel damper in addition to optimal stiffness ratio is presented and compared.
Abstract: The penetration of water and chloride ion into the concrete is of factors that cause rust and corrosion in rebars by reaching the existing reinforcement surface in reinforced concrete structures. In this study, effect of using Asphalt Plant Surplus Filler as a partial replacement of cement with replacement values of 0, 5, 10, 15 and 20% on permeability and electrical resistance of cement mortar were investigated with the aim of decreasing cement consumption. In order to determine the penetration of water, 10 cubic specimens with the size of 150 mm were made and tested. In order to determine chloride ion penetration, 20 cylindrical specimens with a length of 50 and a diameter of 100 mm were studied at the ages of 28 and 56 days. To test the electrical resistivity of cement mortar, 30 cubic specimens with the size of 100 mm were tested at the ages of 7, 28 and 56 days. According to the results of the experiments, adding filler to the cement mortar enhances the penetration of water and chloride ion. Electrical resistivity generally increases with the increase of specimen age. Furthermore, the filler increment indicates the reduction of electrical resistivity.
Abstract: Cyclic loading tests were carried out to research seismic behavior of precast segmental ultrahigh-performance fiber-reinforced concrete (UHPFRC) bridge column with unbonded posttensioned (PT) tendons. Energy dissipation (ED) bars embeded in ultrahigh-performance concrete (UHPC) grout maintained continuous across segment joints and unbonded at the bottom joint. The equivalent method was proposed for ED bars with unbonded length and unbonded PT tendons to obtain the equivalent fiber section conforming to the flat section assumption. A method based on the equivalent plastic hinge model was given to conduct pushover analysis for precast segmental UHPFRC bridge columns. Test results showed that all the specimens exhibited no less than 8% drift capacities, which were remarked with the first fracture of ED bars. Compared with test data, the proposed model was validated to have good accuracy to provide lateral skeleton curve.
Abstract: Based on the Volcanology and Geological Hazard Mitigation Center, Mount Sinabung itself is still at hazardous status up until now that can certainly erupt at any time and sprayed a lot of volcanic material which will lead to the abundance of volcanic ash material in the area of Mount Sinabung. How to optimize the volcanic ash waste is what scientists need to think about. In this study, volcanic ash obtained from Mount Sinabung is used as substitution of fine aggregate in the manufacture of concrete brick (paving block). The variations used were 0%, 25%, 50%, and 75% of the starting weight of the fine aggregate used. From the test results, it is obtained optimum compressive strength of 25.2 Mpa and optimum water absorption of 5.998% which means concrete brick (paving block) meets the classification contained in SNI 03-0691-1996.