...333 STUDY ON REACTIVE POWDER CONCRETE USED IN THE SIDEWALK SYSTEM OF THE QINGHAI-TIBET RAILWAY BRIDGE Ji Wen-yu,1 An Ming-zhe,1 Yan Gui-ping,1 and Wang Jun-min2 1 College of Civil Engineering and Architecture, Beijing Jiaotong University, Beijing, 100044, PRC 2 Beijing Municipal Engineering Research Institute, Beijing, 100007, PRC Abstract The Qinghai-Tibet railway lies in the west area of China at an altitude of more than 4,000 meters. The 576-km railway is being built on frozen earth. The bad climate and sandstorms of the tundra require the concrete of the bridge to have superior mechanical properties and high durability. By adding portland cement, silica fume, superfine fly ash, and superplasticizers, reactive powder concrete (RPC) is used in the sidewalk systems of bridges with compressive strength of 160 MPa. The research shows that RPC has high strength, excellent frost durability, and impermeability. Therefore, RPC is the best choice for the Qinghai-Tibet railway. 1. Introduction The Qinghai-Tibet railway lies in Qinghai-Tibet plateau in the west area of China, at an altitude of more than 4,000 meters and in a high intensity earthquake region. The 576-km railway is being built on frozen earth. The climate conditions are harsh in that area: low air temperature, concentrated rain and snow, and heavy sandstorms. The area also has complicated geology conditions, and groundwater causes corrosion. The 334 International Workshop on Sustainable...
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...REPORT No. 146 (2005) Reactive Powder Concrete N.P. Lee & D.H. Chisholm The work reported here was funded by Building Research Levy. © BRANZ 2006 ISSN: 0113-3675 Preface The low flexural tensile strength of concrete has a number of undesirable consequences for its performance as an effective building material. These include the necessity for auxiliary steel reinforcement and the requirement for thick-sectioned members that are both aesthetically unappealing and consume significant quantities of aggregates. The aggregates are an increasingly scarce resource in many urban areas. An emerging technology with the potential to overcome these limitations is reactive powder concrete (RPC). RPC is a cold-cast cementitious material in which the mechanical properties of the composite matrix are improved by (i) suppression of the weak interfacial transition zone normally developed around the aggregate through improved particle packing and (ii) refinement of the hydrated paste microstructure by extensive use of pozzolanic silica and elevated temperature curing. Tensile capacity is provided by steel micro-fibres rather than conventional reinforcement. The result is a material with the potential for flexural strength up to 50 MPa and ductility and energy absorption values approaching those of steel. The low and non-connected porosity of RPC also render it extremely durable. RPC offers the possibility of building with concrete using slender members in a ‘steel-like’ ...
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...Concrete is the most widely used material in the world. It accounts for roughly 70% of all construction materials globally. Each year about “7 cubic kilometers of concrete are made” (The Civil Engineer). It is a $35 billion industry with more than two million workers in the United States alone (The Civil Engineer). Concrete is made up of cement, water, and chemical admixtures. Portland cement is the most common cement used in concrete. Fly ash, slag cement, sand, or gravel limestone may also be used to create concrete. Due to hydration, the concrete solidifies and hardens after mixing with the water. Concrete is used to make parking structures, roads, foundations, walls, and many other structures (Encyclopedia Britannica Online Academic Edition). Even though concrete is already such a highly used material, there is still room for improvements. Traditional concrete can have many problems including failure under heavy loads, lack of durability, and the cost of repair resulting from failure. Concrete can also be very heavy at times. For example, when designing a bridge the large weight of the asphalt must be accounted for in order to design the supports. In the 1990’s, a group of researchers from the University of Michigan discovered a new form of concrete called bendable concrete. This new mixture is also referred to as Engineered Cementous Composite (ECC). This was achieved by adding stretchable fibers that are embedded in the concrete. Dr. Victor Li was the...
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...Product standardization The tradeoffs that are implied with this move is worth the risk of this approval process. There is potential for savings upwards to HK150,000 per block. An approximate saving of over 1 million based upon the 179 blocks per year projection from the HKHA. Once this approval is agreed upon and the contracts awarded. I recommend a detail review of Unicon current product lines and completely outsourcing the stair production line. After a 6th month time, I recommend we review our production efficiencies and look into expanding our production facility as our three remaining products are now made-to-stock. Issue Identification Concrete Construction Market: • Precast Concrete Products sold to General Contractors in Hong Kong • 2 Options for building, Traditional Method or assembling precast concrete facades & slabs • Not enough market capacity to build all the required buildings 20 market max, 179 needed • Non standardization of precast products available Unicon specific issues: • Specifications do not favor changes at the time of superstructure tender. Time is too short to have them approved. • Shortage of skilled labor •...
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...Waste residues tend to be inert residues mainly constituted by concrete, pavements, gravel, sand and soil. Recycling and reusing these wastes generates a more efficient and green construction, therefore it is important to find a way to recycle these residues in concrete mixtures without affecting the essential properties of concrete. By performing the compressive test in different concrete mixtures that contained different amounts of recycled aggregates from old concretes (20% and 30%), showed that the resistance of the concretes wasn’t significantly affected; less than 2% of the resistance was lost, compared to a concrete mixture that did not have recycled aggregates. Furthermore, when performing the same test to concrete mixtures containing 20%, 30% and 40% of recycled aggregates from construction and demolition (C&D) waste, results showed that up to 25% of its resistance was lost. Therefore, by using either kind of recycled aggregates, up to 30% in a concrete mixture, one is producing a more viable concrete that is not only more economic, but also produces less contamination, enabling the industry to mitigate the environmental impact produced by this industry. Green concretes is an alternative and competitive market that can be created through the acknowledgment that construction and demolition wastes are viable for reusing and recycling as aggregates for any king of concrete, including structural concretes. It’s been observed, that in order to create this competitive market...
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...mixing fresh concrete. With an understanding of concrete properties and the means of which to calculate these properties the students can demonstrate their knowledge in a laboratory environment. The students are expected to achieve this task by designing and mixing a batch of concrete based on specific requirements provided in the ASTM C231. The procedure requirements include strength, slump, air entrainment, volume, aggregate type and size. Students are split into groups and each group is assigned specific parameters to base their designs on. These designs and parameters are used to complete the concrete mixing procedures. The specific parameters for Thursdays Lab Group # 1 were a compressive strength of 8000 psi (55 MPA), limestone aggregate with a maximum size of ¾”. The mixture required moderate air entraining, a supplementary cementitious material called fly ash, and a target slump of 3”- 4”. This design should produce a mixture that is relatively high in strength, durability and workability. The assumption was made that the aggregate properties calculated we accurately described. A sample of this mixture design was created in the lab using the equipment provided. The mixture was then subjected to testing using the slump cone test. The ASTM C231 requires the sample to be tested using an air pot to determine the air content. However, the air pot failed to preform and we were provided with the air content value to aid in continued calculations. The concrete was then placed...
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...Concrete * is a construction material composed of cement and other cementitious materials such as fly ash and slag cement, aggregate, water, and chemical admixtures. * Solidifies and hardens after mixing with water and placement due to a chemical process known as hydration. The water reacts with the cement, which bonds the other components together, eventually creating a stone-like material. Concrete is used to make: * Pavements * Architectural Structures * Pipe * Foundations * Motorways * Bridges * Overpass * Parking Structures * Brick Wall * Block Wall * Gates * Fences There are many types of concrete available, created by varying the proportions of the main ingredients below. By varying the proportions of materials, or by substitution for the cementitious and aggregate phases. The finished product can be tailored to its application with varying strength, density, or chemical and thermal resistance properties. The mix design depends on the type of structure being built, how the concrete will be mixed and delivered, and how it will be placed to form this structure Cement – Portland cement is the most common type of cement in general usage. It is a basic ingredient of concrete, mortar, and plaster. Water – Combining water with a cementitious material forms a cement paste by the process of hydration. The cement paste glues the aggregate together, fills voids within it, and allows it to flow more freely. Aggregates...
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...Concrete as a building material Name: Institution Concrete is a building material which has been in use since the Roman times. It is a complex mixture of water, coarse granular material usually sand or gravel. Cement fills the spaces among the granular material and acts as a binder that glues them together. The Panama Canal, the Hoover Dam, and the Roman Pantheon are some of renowned structures made of concrete. (PCA) Concrete usage dates back thousands of years ago. Concrete was used for building of many ancient structures. Heinrich Schliemann, a German archaeologist discovered concrete floors in a royal palace of Tiryns, Greece, which dates approximately 1400-1200 BC. The Romans also used concrete on large scale from 300 BC to 476 AD. Roman concrete was made from an aggregate of pumice, pozzolana and quicklime. (Jacobs 4). Modern concrete is different from the Romans concrete in two ways. First, its mixer of a homogeneous fluid, this allows it to be poured into forms instead of hand-layering together with the arrangement of gravel, in Roman practice, this comprised of debris. Second, modern cement is integrated with steel that reinforces it to great strength in tension. Roman concrete depended only on the strength of the concrete bonds to withstand tension. The idea of reinforced concrete was invented by Joseph Monier in 1849. The first reinforced concrete bridge was built that year. (Constructor) Concrete has many benefits. It is economical when ingredients are readily...
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...Strengthening Concrete with Keratin Fibers from Chicken Feathers Austin Allen Kennesaw Mountain High School Table of Contents Research Problem 3 Chapter II: Literature Review 4 Keratin Fibers 4 Concrete 4 Compressive Strength 5 Tensile Strength 5 Chicken Feathers 5 Structure 6 Glossary 6 Chapter III: Methodology 6 Analysis Plan 7 Validity 7 Assumptions 7 Scope and Limitations 8 Chapter IV: Analysis 8 Chapter V: Conclusions and Recommendations 9 References 10 Strengthening Concrete with Keratin Fibers from Chicken Feathers Chicken feathers are primarily used for making feather meal for farm animals; however, chicken feathers are also used in the production of plastics, fishing flies, biodegradable pots and plastics, bio-diesel fuel, hurricane-resistant roofing, and the stuffing in pillows (Fan, 2008). Applying these uses of chicken feathers to concrete could increase the strength and life of the structure built; for example, an office building could potentially last years longer if the concrete used to construct it (contained more strength) to hold up the structure. Furthermore, the wear and tear of the strength of the building would be approximately the same; however, the capacity to support the structure would be greater due to an increased initial strength (Fan, 2008). Worrell, Price, Martin, Hendricks, and Meida (2001) reported that approximately five percent of the global carbon dioxide emissions come from the pouring of Portland...
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...different aspects of concrete which is the mixture of crushed stones, sand, cement and water. There are many types of concrete suggested to be used together with their ingredients namely extenders and admixtures. The report is a brief summary on special concretes and their applications such as High performance concrete, Self-consolidating concrete, High strength concrete and etc that will be used in the construction of a new garage for AB motors which will begin in the new year outside Bloemfontein. Again, different types of extenders that will also be applied in the project are also discussed with their applications. To name the few, those extenders are Ground granulated blust furnace slag and Fly ash (FA). Finally the report will also entertain on different kinds of admixtures and their applications as well...
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...SYNOPSIS ON DEVELOPMENT AND PERFORMACE OF CONCRETE USING SUPPLEMENTARY MATERIALS SUBMITTED BY: RAGHAV M Tech (STRUCTURAL ENGINEERING) DEVELOPMENT AND PERFORMACE OF CONCRETE USING SUPPLEMENTARY MATERIALS OBJECTIVE: 1.The main objective of this study is to investigate the use of various supplementary materials for preparing concrete. 2.To compare...
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...Introduction The development of Roman concrete is of uncertain origin, but it’s one of the biggest reasons that Rome managed to build such massive structures and maintain such a massive empire, especially considering its use in long-lasting seaports and population-maintaining aqueducts. It was cheap, easily moldable, strong, portable, easily made, and could be used for mortar in addition to being used purely as a building material. Indeed, there are ports made of Roman concrete have been standing for over two thousand years (Yegül, n.d.). Add to this Roman arches, those large, vaulted things that utilized the strength of concrete and the ingenuity pioneered by the Sumerians to dissipate force out and across the curve of an arch, and the Romans were set to define...
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...1. Before we explain photocatalytic concrete ill review and explain sustainability. READ SLIDE Sustainability should be more than just not using up all the resources, but replenishing them as well. It is important that we fully understand sustainability so that its implementation becomes more predominant and we achieve a sustainable prosperity. 2. As the Vinn diagram show Sustainability is an overlapping balance of three major components, ECONOMIC, SOCIAL, and ECO-LOGICAL. To achieve sustainability, non of the three can jeopardize one or the other 3. To get a better understanding I put it In my own words Sustainability should be defined as allowing all humans to live with their basic needs met but leaving the opportunity to pursue our lives in satisfaction without risking or denying others in the present and future to do the same. To do this, we must be innovative when using resources and allow ourselves room to restore them to full capacity, without furthering the de gradation of the Earth’s systems. 4. As we may already know Concrete has established itself as the most important building material worldwide with a production estimated at 10 billion tons each year. 5. Unfortunately popularity comes with a significant price, and which until recently has been too far overlooked 6. Alone, for the sheer volumes produced each year, concrete has inherited an enormous negative impact on the environment. The concrete industry has become a victim of its...
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...A Project report on “HIGH PERFORMANCE CONCRETE” BY ABHISHEK AGARWAL -10/ICE/005 ABHISHEK VISHWAKARMA -10/ICE/009 SACHIN TIWARI -10/ICE/042 VAIBHAV KUMAR -10/ICE/055 VISHWAS MISHRA -10/ICE/064 UTKARSH YADAV -10/ICE/065 VIKASH VASHISHTH -10/ICE/067 Under the Guidance of- Dr. SHILPA PAL Gautam Buddha University SCHOOL OF ENGINEERING GAUTAM BUDDHA UNIVERSITY ACKNOWLEDGEMENT We take immense pleasure in thanking Dr. Shilpa Pal for having permitted us to carry out this project work. We wish to express our deep sense of gratitude to Er. Lallan Sharma (Quality Control Engineer) in SIMPLEX INFRASTRUCTRE Pvt. Ltd. and Mr. Avnish Nagar (Quality control Manager) in J.P SPORTS CITY School of Engineering, Gautam Buddha University for his able guidance and useful suggestions, which helped me in completing the project work, in time. Finally, yet importantly, we would like to express my heartfelt thanks to our beloved parents for their blessings, friends/classmates for their help and wishes for the successful completion of this project. INDEX TOPIC ...
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...Concrete Repair, Rehabilitation and Retrofitting II – Alexander et al (eds) © 2009 Taylor & Francis Group, London, ISBN 978-0-415-46850-3 Performance of Reactive Powder Concrete (RPC) with different curing conditions and its retrofitting effects on concrete member T.P. Chang, B.T. Chen, J.J. Wang & C.S. Wu Department of Construction Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ROC ABSTRACT: The material performance of Reactive Powder Concrete (RPC) with two different curing conditions, water-curing of 25ºC and steam-curing of 85ºC and 95% relative humidity, were studied experimentally. The reinforcing effects of the RPC with two wrapping thicknesses of 10 and 15 mm, respectively, on the surface of cylindrical concrete specimen were evaluated. Major experimental results show both the engineering properties and indices of durability of RPC with steam-curing at four different ages have substantially increased except for the supersonic pulse velocity and dynamic moduli of elasticity and shear. The ratio of increase of compressive strength of cylindrical specimens retrofitted with 10 and 15 mm of wrapping RPC are in the range of 9.5 to 38.0%. 1 INTRODUCTION Reactive powder concrete (RPC), a cement-based composite material well known for the ultra-highstrength, high-durability and low-porosity, made its international debut in 1994 (Richard, 1994). The advance mechanical and physical properties of RPC are obtained by optimizing...
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