Development, Characterization and Modeling of Ultra-high Performance Concrete (UHPC) with Locally Available Materials

Development, Characterization and Modeling of Ultra-high Performance Concrete (UHPC) with Locally Available Materials
Author: Zhidong Zhou
Publisher:
Total Pages: 237
Release: 2018
Genre:
ISBN:

Ultra-high performance concrete (UHPC) is a new generation of advanced cementitious materials with superior mechanical properties that far surpass conventional concrete. However, UHPC is expensive and proprietary, and only a few field producers are available commercially in the United States. Moreover, its tensile behavior has not been well understood. This research aims to develop, characterize and model UHPC, specifically for its tensile behavior. Two viable UHPC mixes produced with locally available materials are developed, and they exhibit comparable mechanical properties to those of commercial products. An effective specimen for direct tension test (DTT) is designed and then used to evaluate both the short- and long-term tensile behavior of UHPC. The extended freeze-thaw actions have obvious impact on the tensile responses of UHPC, particularly over the post-cracking period, and the energy-based evaluation approach from DTT is more critical than the modulus-based approach to screen and evaluate material deterioration over freeze-thaw period. An analytical model is proposed to predict the tensile responses of UHPC from the bridging behavior of matrix and fibers. A fiber reinforcement efficiency function is derived to characterize the combined effects of fiber orientation, fiber snubbing and matrix spalling on the tensile behavior of UHPC. The fiber geometry and volume fraction, interfacial bond strength, and fiber reinforcement efficiency pronouncedly govern the tensile strength and hardening behavior of UHPC. The prediction capability of the analytical model is greatly improved by adjusting some coefficients that govern the hardening and softening branches of tensile stress-crack width curves. This model can effectively predict the tensile behavior of UHPC and its deterioration effect due to freeze-thaw actions. The non-contacted lap-splice pullout test is conducted to investigate the bond behavior of rebar in UHPC. The adopted analytical model can predict the bond stress-slip relation accurately. The critical embedment length and bond strength of rebar in UHPC mixes are recommended for bridge deck connection design. The comprehensive study on the tensile behavior of UHPC presented sheds light on better understanding UHPC performance in tension and provides both the experimental and analytical methods to effectively evaluate its tensile behavior.

High-Performance Eco-Efficient Concrete

High-Performance Eco-Efficient Concrete
Author: Carlos Thomas
Publisher: MDPI
Total Pages: 278
Release: 2021-05-26
Genre: Technology & Engineering
ISBN: 3036508600

This book is dedicated to “High-Performance Eco-Efficient Concrete” and concrete fatigue behavior, more sustainable construction materials, capable of complying with quality standards and current innovation policies, aimed at saving natural resources and reducing global pollution. The development of self-compacting concretes with electric arc furnace slags is a further achievement. In addition, the technical and economic viability of using coarse recycled aggregates from crushed concrete in shotcrete, enhanced quality and reduced on-site construction time are the basic features of prefabricated bridge elements and systems, biomass bottom ash as aluminosilicate precursor and phosphogypsum were discussed. On the other hand, basalt fiber improving the mechanical properties and durability of reactive powder concrete, alkali-activated slag and high-volume fly ash and the potential of phosphogypsum as secondary raw material in construction industry, the effects of fly ash on the diffusion, bonding, and microproperties of chloride penetration in concrete were studied. Increasing amounts of sustainable concretes are being used as society becomes more aware of the environment. Finally, the circular economy as an economic model of production and consumption that involves reusing, repairing, refurbishing, and recycling materials after their service life are presented in this book.

Lowering the Cost of Ultrahigh-performance Concrete Via Design and Performance Evaluation of Non-Proprietary Mixtures

Lowering the Cost of Ultrahigh-performance Concrete Via Design and Performance Evaluation of Non-Proprietary Mixtures
Author: Deepika Sundar
Publisher:
Total Pages: 0
Release: 2023
Genre:
ISBN:

The new infrastructure bill promises to invest in repairing and replacing the aging critical infrastructure in the US, particularly roads and bridges. Ultrahigh-performance concrete (UHPC) is a "robust solution for highway infrastructure" since the high compressive strength (>120 MPa), high tensile strength (>5 MPa), homogeneity, and the superior durability of UHPC make it highly reliable wherever it is used (Du et al. 2021). This research aimed to produce and evaluate the performance of low-cost UHPC mixtures using local ingredients. To that end, in the first section of this dissertation, a database consisting of 139 mixture proportions of non-proprietary UHPC formulations, and their workability (flow) and compressive strength data was developed. This database was expanded using prior data of 83 UHPC mixtures developed at Penn State. Random forest-based machine learning (ML) models were developed using this data to first predict the mixtures' flow and compressive strength. Further, physics-based knowledge of the impact of particle size (of aggregates and cementitious materials), particle packing, and chemical composition of the cement was incorporated into the model. This endeavor improved the generalizability of prediction models. In the second part of the dissertation, 130 UHP mortar and concrete mixtures were developed using local ingredients and were evaluated. A plan was devised and executed to determine the impact ingredient properties, mixture proportions, and the temperature of fresh concrete on the properties of UHPC. This experimentation also allowed insight into the robustness of the developed UHPCs to quantify their sensitivity to variability in the mixture constituents and proportions. This research study determined lower-cost alternatives for expensive mixture constituents like quartz filler and quartz sand. At the end of this section, several low-cost UHPC mixtures were developed that met the requirements of FHWA and AASHTO guidelines. Reliably characterizing the mechanical performance, especially the tensile-stress-strain behavior of UHPC mixtures, is critical to determine whether the UHPC exhibited strain-hardening behavior. However, measuring this response by applying uniform loading in tension without pre-maturely cracking the test specimens or inducing large bending strains in the process is challenging. Therefore, in the third section of the dissertation, a UHPC tensile testing setup in compliance with the AASHTO T397-22 test method was built. This set-up involved equipping an 11-kips load cell with custom-made flat grips fabricated following AASHTO recommendations. In addition, an aluminum extensometer was fabricated to measure the average strain in the gauge section, and a data acquisition system was set up to accurately record the load and displacement signals. As a result, the mixtures' extent of strain hardening, and pre-crack localization strain capacity were consistently determined. This setup further allows for the optimization of the fiber reinforcement to reduce the cost of UHPC. Finally, a comprehensive literature review was carried out with the objective of assessing the risk of, and formulating strategies to mitigate, shrinkage cracking in UHPC mixtures. UHPC mixtures tend to be dominated by cementitious materials, composing greater than 60% of the volume of concrete. A high content of cementitious materials and low water-to-cementitious material (w/cm) ratio render UHPC mixtures vulnerable to shrinkage cracking and damage, particularly in connections between prefabricated bridge elements. Thus, the last part of the dissertation reviewed the risk of shrinkage-based cracking in UHPC, the role of fiber reinforcement, and finally assessed the effectiveness of mitigation measures. The outcome of this dissertation is the reduction of the cost of non-proprietary UHPC that were compliant with and exceeded FHWA and AASHTO design guideline performance. It also adds to the know-how in the reliable production of low-cost non-proprietary UHPC mixtures by offering consistently produced and collected data. ML modeling offers efficient and robust tools for future UHPC producers to optimize UHPC mix designs with minimal trial and error.

Concrete : Microstructure, Properties, and Materials

Concrete : Microstructure, Properties, and Materials
Author: P. Mehta
Publisher: McGraw Hill Professional
Total Pages: 684
Release: 2005-09-26
Genre: Technology & Engineering
ISBN: 0071462899

This textbook presents the art and science of concrete in a simple, clear, hands-on manner, focusing on the following: Cement and concrete are predicted to be the premier building material of the 21st Century; Includes unique diagrams, photographs, and summary tables; Updated to include new chapters on non-destructive methods for concrete; future challenges in concrete technology; an increased number of examples of concrete applications; and new developments in durability.

Proceedings of the 1st International Conference on Sustainable Waste Management through Design

Proceedings of the 1st International Conference on Sustainable Waste Management through Design
Author: Harvinder Singh
Publisher: Springer
Total Pages: 616
Release: 2018-10-30
Genre: Science
ISBN: 3030027074

This book describes the latest advances, innovations and applications in the field of waste management and environmental geomechanics as presented by leading researchers, engineers and practitioners at the International Conference on Sustainable Waste Management through Design (IC_SWMD), held in Ludhiana (Punjab), India on November 2-3, 2018. Providing a unique overview of new directions, and opportunities for sustainable and resilient design approaches to protect infrastructure and the environment, it discusses diverse topics related to civil engineering and construction aspects of the resource management cycle, from the minimization of waste, through the eco-friendly re-use and processing of waste materials, the management and disposal of residual wastes, to water treatments and technologies. It also encompasses strategies for reducing construction waste through better design, improved recovery, re-use, more efficient resource management and the performance of materials recovered from wastes. The contributions were selected by means of a rigorous peer-review process and highlight many exciting ideas that will spur novel research directions and foster multidisciplinary collaboration among different waste management specialists.

Concrete Mixture Proportioning

Concrete Mixture Proportioning
Author: Francois de Larrard
Publisher: CRC Press
Total Pages: 450
Release: 1999-03-04
Genre: Architecture
ISBN: 9780419235002

The design of concrete mixes is becoming increasingly complex, with the addition of new materials in the compounds, such as organic admixtures, fibres and supplementary cementitious materials. Moreover, the list of properties which concretes are required to possess for certain applications has increased, and interest is developing in rheology, durability, deformability and whole-life behaviour. This book presents a number of simple models for the understanding of a concrete system, and provides the techniques for developing more sophisticated models for the practical design of concrete mixes.

Design and Control of Concrete Mixtures

Design and Control of Concrete Mixtures
Author: Steven H. Kosmatka
Publisher:
Total Pages: 224
Release: 1988
Genre: Technology & Engineering
ISBN:

Portland Cement Association reference, dealing with fundamentals, cold weather concreting, curing, admixtures, aggregates, mixing, and much more.

Designing and Building with UHPFRC

Designing and Building with UHPFRC
Author: Jacques Resplendino
Publisher: John Wiley & Sons
Total Pages: 678
Release: 2013-01-29
Genre: Technology & Engineering
ISBN: 1118587553

This book contains the proceedings of the international workshop “Designing and Building with Ultra-High Performance Fibre-Reinforced Concrete (UHPFRC): State of the Art and Development”, organized by AFGC, the French Association for Civil Engineering and French branch of fib, in Marseille (France), November 17-18, 2009. This workshop was focused on the experience of a lot of recent UHPFRC realizations. Through more than 50 papers, this book details the experience of many countries in UHPFRC construction and design, including projects from Japan, Germany, Australia, Austria, USA, Denmark, the Netherlands, Canada... and France. The projects are categorized as novel architectural solutions, new frontiers for bridges, new equipments and structural components, and extending the service life of structures. The last part presents major research results, durability and sustainability aspects, and the updated AFGC Recommendations on UHPFRC.