Reduced Cementitious Material in Optimized Concrete Mixtures PDF Download

Author: Peter Taylor
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 163

View

Book Description
This document reports the activities and observations of a research team that performed on-site and laboratory testing of concrete mixtures with reduced cementitious materials content placed in two cells at the MnROAD facility in Albertville, Minnesota. The overall objectives of this research project included investigating the early age characteristics of concrete paving mixes containing reduced cementitious contents as well as their long-term performance. It was observed that while workability was marginal in the mixture proportioned with 470 lb/yd3, all other properties of the test sections were similar to those of the control section.

Author: John S. Lawler
Publisher: Transportation Research Board
ISBN: 0309098971
Category : Aggregates (Building materials)
Languages : en
Pages : 130

View

Book Description
NCHRP Report 566 is designed to help facilitate the use of supplementary cementitious materials to enhance durability of concrete used in highway construction, especially bridge decks. The report includes a methodology for selecting optimum concrete mixture proportions that focuses on durability aspects of concrete and the performance requirements for specific environmental conditions. The methodology is presented in a text format and as a computational tool, in the form of a Visual Basic?driven Microsoft Excel spreadsheet. Background information and a hypothetical case study was published as NCHRP Web-Only Document 110: Supplementary Cementitious Materials to Enhance Durability of Concrete Bridge Decks. The Statistical Experimental Design for Optimizing Concrete (SEDOC), the computational tool for the concrete mixture optimization methodology, and the user?s guide are available in a ZIP format for download.

Author:
Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 72

View

Book Description
This project was designed to explore the feasibility of lowering the cementitious materials content (CMC) used in Wisconsin concrete pavement construction. The cementitious materials studied included portland cement, fly ash, and ground granulated blast furnace slag. For the first phase, mixtures were prepared using the current WisDOT aggregate grading specification. For the second phase, mixtures were prepared using an optimized (e.g. Shilstone) gradation. A variety of tests for fresh and hardened concrete were conducted to determine the viability of low CMC mixtures for use in concrete pavement.

Author: Adam Rudy
Publisher: Purdue University Press
ISBN: 9781622602582
Category : Transportation
Languages : en
Pages : 70

View

Book Description
The ultimate goals of this study included investigation of the optimal ranges for paste content, amount of cementations materials and aggregate gradation for concrete paving mixtures. In general, the optimum concrete mixtures developed in this study contained low paste content (below 23%), and were characterized by low scaling and sorptivity. In addition, it was also possible to achieve high cement replacement levels for these mixtures. Finally, for optimized fly ash mixtures, the selection of well graded aggregate gradation with high packing density increased the most desired paste content for those mixtures, thus indicating that combined aggregate gradation has strong influence on concrete performance. Lastly, concrete mixtures developed with optimum ranges of variables studied in this research contained low cement content. The overall scope of the research was divided into three distinctive phases, each of which is described briefly below: PHASE I: This phase consisted of statistical optimization of the proportions of concrete binder. The Central Composite Design methodology (CCD) was used to design the experiment for the optimization of binder in three types of concrete mixtures: a) cement + fly ash, b) cement + GGBFS, and c) cement + fly ash + GGBFS. The variables studied in each of these systems included: paste content (from 21 to 25 % by mixture volume) and total content of supplementary cementitious material (SCM) in the mixture. This was expressed as weight percent of total binder, and varied depending on the binder system used. PHASE II: The main goal of this phase was to investigate the effect of different aggregate gradations on the fresh and hardened properties of optimized concrete mixtures developed in PHASE I, as well as to identify the most desired aggregate gradations for paving mixtures. Different aggregate gradations were prepared by blending of 2, 3 or 4 different sizes of aggregates based on concept of Shilstone's Coarseness Factor Chart. PHASE III: The concept of air-free paste-aggregate void saturation ratio (k") introduced in PHASE II seemed to fairly accurate link the properties of concrete mixtures with their paste content. Thus, it was decided to further investigate this concept in connection with aggregate packing density ( ). In addition, it was believed that defining optimum values of "k" will allow for revising the paste content ranges developed in PHASE I for different systems, and thus define more general optimum paste ranges for paving mixtures.

Author: Adel Baghdady
Publisher:
ISBN:
Category :
Languages : en
Pages : 22

View

Book Description
This paper studies the effectiveness of applying value engineering to actual concrete mixtures. The study was conducted in the State of Qatar on a number of strategic construction projects with international engineering specifications for the 2022 World Cup projects. The study examined the concrete mixtures of Doha Metro project and the development of KAHRAMAA's (Qatar Electricity and Water Company) Abu Funtas Strategic Desalination Plant, in order to generally improve the quality and productivity of ready-mixed concrete used in construction and hydraulic projects. The application of value engineering to such concrete mixtures resulted in the following: • Improving the quality of concrete mixtures and increasing the durability of buildings in which they are used; • Reducing the waste of excess materials of concrete mixture, optimizing the use of resources, and enhancing sustainability; • Reducing the use of cement, thus reducing CO2 emissions which ensures the protection of environment and public health; • Reducing actual costs of concrete mixtures and, in turn, reducing the costs of construction projects; and • Increasing the market share and competitiveness of concrete producers. This research shows that applying the methodology of value engineering to ready-mixed concrete is an effective way to save around 5% of the total cost of concrete mixtures supplied to construction and hydraulic projects, improve the quality according to the technical requirements and as per the standards and specifications for ready-mixed concrete, improve the environmental impact, and promote sustainability.

Author: Waleed Faleh Almutairi
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 114

View

Book Description
Portland cement is an essential ingredient in concrete. The use of cement is to enhance the strength as well as other hardened properties of concrete mixtures. Determining the accurate amount of cement is important because the required strength may not be achieved if not enough cement is used. By contrast, when using too much cement, concrete cracking may occur that leads to reducing durability. Researchers at the University of Arkansas (UA) have shown that many bridge decks achieve their 28 day design strength of 4000 psi by 7 days of age. Bridge decks having high strength may experience cracking, which affects the durability. The Arkansas State Highway and Transportation Department (AHTD) classifies two types of concrete mixtures that can be used in bridges. The first is Class S concrete, and the second is Class S(AE). Class S is used for the structural components and does not contain air entrainment while Class S (AE) is mainly used for bridge decks and contains air entrainment. AHTD requires the same minimum cementitious material content for both classes of concrete. The purpose of this research is to determine if the cementitious material content of Class S mixtures can be reduced while still meeting AHTD specifications. The research program examined cementitious material content, Class C fly ash content, and water to cementitious material ratio (w/cm) . For all mixtures, selected fresh and hardened concrete properties were measured to ensure that they complied with AHTD requirements.

Author: Avijit Chaubey
Publisher: CRC Press
ISBN: 1000766667
Category : Technology & Engineering
Languages : en
Pages : 185

View

Book Description
Practical Concrete Mix Design has been compiled to help readers understand the concrete mix design methodology, including formulas and tables involved in the pertinent steps. This book helps engineers understand the mix design procedure, through illuminating every possible explanation for each step of mix design, limitations given by standards, and practical guides on tailor-making concrete to meet specific requirements. The construction industry needs engineers/experts who can reduce the costs of concrete, and thereby increase their profitability. This book shows effective methods for optimizing concrete and simultaneously achieving the desired properties of concrete. It covers why, how, and when with respect to concrete proportioning and optimization. It further provides the necessary skills for engineers to hone their skills in doing so, understanding the risks involved, and troubleshooting related problems.

Author: Miras Mamirov
Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 109

View

Book Description
The main objective of this study was to evaluate the effect of aggregate particle packing optimization and cement reduction on Nebraska slip-form pavement concrete performance. A literature review was conducted to examine different aggregate optimization tools, quality control tests, and historical data of Nebraska Department of Transportation (NDOT) mixtures. It was found that the Modified Toufar Model has good potential in optimizing particle packing and predicting packing degrees. The combined void content test was found to be useful to experimentally justify optimized aggregate gradations. Two specific pavement concrete workability tests, i.e., the Box Test and the VKelly Test, were used to evaluate the effect of cement reduction and optimized aggregate gradation on pavement concrete workability. The Box Test ranking was modified to provide a more detailed and objective evaluation. Analysis of different aggregate combinations has shown that experimental packing from the combined void content test has a high correlation with estimated packing from the Modified Toufar Model. Results showed that when the optimized aggregate gradation is used, cement content can be effectively reduced by up to 1.0 sack (94 lb/yd3) without compromising the fresh properties, mechanical properties, and permeability. Based on the results of free and restrained shrinkage, it was justified that shrinkage and cracking potential can be reduced in optimized concrete mixtures. Freeze/thaw resistance can be slightly improved with optimized mixtures. A mix design improvement procedure considering both theoretical and experimental packing and the minimum excess paste-to-aggregate ratio can be used to design concrete with an optimum cement content.The main objective of this study was to evaluate the effect of aggregate particle packing optimization and cement reduction on Nebraska slip-form pavement concrete performance. A literature review was conducted to examine different aggregate optimization tools, quality control tests, and historical data of Nebraska Department of Transportation (NDOT) mixtures. It was found that the Modified Toufar Model has good potential in optimizing particle packing and predicting packing degrees. The combined void content test was found to be useful to experimentally justify optimized aggregate gradations. Two specific pavement concrete workability tests, i.e., the Box Test and the VKelly Test, were used to evaluate the effect of cement reduction and optimized aggregate gradation on pavement concrete workability. The Box Test ranking was modified to provide a more detailed and objective evaluation. Considering one of the goals of the study was to maximize the use of local materials, locally available cementitious materials and aggregates from East and West Nebraska were selected. Analysis of different aggregate combinations has shown that experimental packing from the combined void content test has a high correlation with estimated packing from the Modified Toufar Model. Results also demonstrated that the current aggregate combination is not the optimum gradation and can be improved. The experimental program included in this study consisted of three Phases. Phase 1 focused on obtaining promising aggregate blends by maintaining the standard cement content (564 lb/yd3, 335 kg/m3). Fresh concrete properties were the main criteria to select promising blends. Phase 2 included an evaluation of performance of pavement concrete with cement content reduced by 0.5 sack (47 lb/yd3, 28 kg/m3) steps for other reference and optimized aggregate blends. Results justified that when optimum gradation is used, cement could be reduced up to 94 lb/yd3 (56 kg/m3). Phase 3 is the performance evaluation phase, which included evaluating the reference mix and selected promising mixes for setting time, modulus of elasticity, free shrinkage, restrained shrinkage, and freeze/thaw resistance. Mixtures with reduced cement and optimized aggregate gradation have shown improved freeze/thaw resistance and lower shrinkage rate. Finally, a mix design improvement procedure incorporating theoretical and experimental particle packing and using excess paste-to-aggregates ratio as the control parameter was proposed. To sum up, the study has justified that the Modified Toufar Model and the combined void content test can be useful tools in aggregate gradation optimization. In order to evaluate workability of pavement concrete more accurately, the Box Test ranking was modified based on image analysis of surface and edge quality. It was also proved that mixtures with reduced cement content and optimized aggregate gradation perform better in terms of freeze/thaw resistance and shrinkage.

Author: Hosam Saleh
Publisher: BoD – Books on Demand
ISBN: 1839623144
Category : Technology & Engineering
Languages : en
Pages : 238

View

Book Description
Cement is the basis of the building and construction industry and of fundamental importance for many civil engineering applications. As such, the cement industry is one of the key industries worldwide necessary for the current and future sustainable development of society. Despite its undisputed importance, the cement industry is one of those industrial branches predominately responsible for high energy consumption and excessive generation of large amounts of carbon dioxide and other contaminants that significantly endanger human health and the environment and contributes to global warming.In this context, nanomaterials, polymeric materials, and natural additives are being used for cement enhancement in various applications. This book examines these novel materials and their optimization, characterization, and sustainable application in the building industry and for stabilizing hazardous waste.

Author: Keyur Dhawan
Publisher:
ISBN:
Category : 3D printing parameters
Languages : en
Pages : 0

View

Book Description
3D Printing Technology is one of the most progressive technologies which is rapidly growing in the world of construction. This technology benefits by fast-tracking the speed of construction and reducing the labor cost, which allows more benefit economically and even providing structures with aesthetical looks, better strength and, durability aimed to be as good as casted concrete structures. To optimize the mix design and produce a workable concrete structure, Fused Deposition Modeling has been used for the printing process. The study is done to produce optimized proportions of concrete mix designs that are suitable for 3D printing of concrete. The addition of silica fume, nano- clay, and fly ash as non- cementitious material and superplasticizers, retarders, accelerators, and viscosity admixtures as chemical dosages are reported to control the flow of the concrete, bonding between the ingredients in the matrix and slowing down the hydration process, respectively which provides the structure with better stability. The 3D printing parameters like time, printability window, pressure variation, and other mechanical properties are studied in this research. FE- analysis can analyze the buildability of a specific shape or structure before printing. So that it can save the cost of materials and help with reducing the formation of 3D printed structure. Keywords: Supplementary Cementitious materials, Chemical Dosage, 3D printing parameters, and FE analysis.