Development Of Specifications For Modified Engineered Cementitious Composites Mecc For Use As Bridge Deck Overlays In Nevada

Engineered cementitious composite (ECC) material is a high-strength, fiber-reinforced, ductile mortar mixture that can exhibit tensile strains of up to 5%. The durability and mechanical properties of ECC make it a desirable construction material. This study presents an extensive evaluation of modified engineered cementitious composite (MECC) using locally sourced raw materials for use as a bridge-deck-overlay material. MECC is a mixture of cement, fly ash, water, concrete sand, and poly-vinyl alcohol fibers. The concrete sand used in this study was used in lieu of the typically used silica sand to reduce the high material cost, which makes MECC a modified ECC mix. Currently, the Nevada Department of Transportation (NDOT) uses a polymer concrete for bridge-deck-overlays in Nevada. While NDOT has had good performance with the polymer concrete overlays, the polymer concrete material is an expensive proprietary material. NDOT believes that MECC may be a viable alternative to the polymer concrete as a bridge-deck-overlay material. In this study, three different representative aggregates from throughout Nevada were selected to understand how the local aggregates would perform in MECC mixes. In total, eighteen different MECC mixes were evaluated using a total of thirteen different tests to determine the fresh and hardened properties of the MECC material. These tests included compressive strength, freeze-thaw durability, resistance to chloride ion penetration, and drying shrinkage. Additionally, a uniaxial tensile test was developed to test the tensile strengths and tensile strains of these different MECC mixes. In addition to evaluating MECC, samples of the polymer concrete and of a traditional Portland cement concrete mix were also tested. These results were used to determine how the performance of the MECC material compares with polymer concrete and traditional concrete. The laboratory test results were then analyzed using several different statistical analyses. First, all of the MECC mixes were compared with each other, and the polymer concrete and traditional concrete mixes. This showed how many mixes had statistically significantly higher/lower performance that both the polymer concrete and traditional concrete. Second, linear regressions were used to determine the standardized regression coefficients (or beta coefficients) which were used to determine which variables (mix proportions, aggregate source, fiber type) influenced the MECC's properties. Third, additional MECC mixes were batched to determine which aggregate properties would influence the MECC's properties. From this analysis, several predictive models were developed to predict the properties of an MECC mix that used a specific fine aggregate stockpile. After the completion of the laboratory phase, three different field trials were conducted to determine the feasibility of batching large amounts of MECC at commercial concrete batch plants. In these trials, approximately 6 cubic yards of MECC was mixed using different plant configurations to determine if any special measures would be needed to mix MECC on a large-scale. Additionally, a trial slab of MECC was placed at each of these field trials to determine how easy the MECC material would be to place, consolidate, and finish. The findings of this study are that MECC has many desirable qualities of a bridge-deck-overlay material. MECC has higher compressive strengths, higher tensile strengths and strains, high resistance to chloride ion penetration, and higher abrasion resistance than traditional concrete. Additionally, MECC has similar performance to the polymer concrete, meaning there is not a significant drop in performance between the materials. The large-scale trial batches showed that MECC could be mixed on a large-scale without any special measures. While MECC is harder to place than traditional concrete, it is not expected to require any specialty equipment for placement. The findings of this study were used to draft a specification for NDOT for the use of MECC as a bridge-deck-overlay material. This specification will be used in an upcoming field project by NDOT where a bridge-deck-overlay measuring approximately 28 feet by 140 feet by 4 inches thick will be placed in the spring of 2016 in Northern Nevada.

Engineered cementitious composite (ECC) material is a high strength, fiber-reinforced, ductile mortar mixture that can exhibit tensile strains of up to 5%. ECC has a dense matrix, giving the material exceptional durability characteristics. The durability and mechanical properties of ECC make it a desirable, though expensive, construction material. This study presents an extensive evaluation of modified engineered cementitious composite (MECC) using locally sourced raw materials for use as a bridge deck overlay material. MECC is a mixture of cement, fly ash, water, concrete sand, and poly-vinyl alcohol fibers. The concrete sand used in this study was used in lieu of the typically used silica sand to reduce the high material cost for ECC. Three different representative aggregates from throughout Nevada were selected to understand how the local aggregates would perform in MECC mixes. In total, eighteen different laboratory mixes of MECC were evaluated using multiple performance and mechanical tests. After the completion of the laboratory phase, two different field trials were conducted to determine the feasibility of batching large amounts of MECC at commercial concrete batch plants.

This synthesis wil be of interest to materials engineers, construction engineers, maintenance engineers, pavement contractors and others interested in the use of latex-modified mortars (LMM) and concretes ( LMC). Information is provided on material properties of various LMM and LMC, as well as current construction practices used for LMM and LMC. Potential applications for LMM and LMC are also included. The use of innovative modified portland cement mortars and concretes for construction and maintenance applications is growing. This report of the Transportation Research Board describes the current state of the practice with respect to the use of latex-modified portland cement concretes and mortars. The extent of use of each material (including case histories), based on results of surveys of state highway agencies and a review of the literature, is summarized.

Premature failure of portland cement concrete bridge decks is of national concern, particularly in those areas where chloride residues accumulate in the concrete from winter deicing operations. West Virginia's research and field usage indicates that the application of a relatively thin (1 to 2-in.) overlay of portland cement concrete or mortar containing a latex modifier may result in a significant increase in the useful life of bridge decks. Eighteen structures, including both new construction and renovation of existing decks, have received the latex-modified concrete overlay. Results to date have been most encouraging.

Up-to-date coverage of bridge design and analysis revised to reflect the fifth edition of the AASHTO LRFD specifications Design of Highway Bridges, Third Edition offers detailed coverage of engineering basics for the design of short- and medium-span bridges. Revised to conform with the latest fifth edition of the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications, it is an excellent engineering resource for both professionals and students. This updated edition has been reorganized throughout, spreading the material into twenty shorter, more focused chapters that make information even easier to find and navigate. It also features: Expanded coverage of computer modeling, calibration of service limit states, rigid method system analysis, and concrete shear Information on key bridge types, selection principles, and aesthetic issues Dozens of worked problems that allow techniques to be applied to real-world problems and design specifications A new color insert of bridge photographs, including examples of historical and aesthetic significance New coverage of the "green" aspects of recycled steel Selected references for further study From gaining a quick familiarity with the AASHTO LRFD specifications to seeking broader guidance on highway bridge design Design of Highway Bridges is the one-stop, ready reference that puts information at your fingertips, while also serving as an excellent study guide and reference for the U.S. Professional Engineering Examination.

The Singularity. It is the era of the posthuman. Artificial intelligences have surpassed the limits of human intellect. Biotechnological beings have rendered people all but extinct. Molecular nanotechnology runs rampant, replicating and reprogramming at will. Contact with extraterrestrial life grows more imminent with each new day. Struggling to survive and thrive in this accelerated world are three generations of the Macx clan: Manfred, an entrepreneur dealing in intelligence amplification technology whose mind is divided between his physical environment and the Internet; his daughter, Amber, on the run from her domineering mother, seeking her fortune in the outer system as an indentured astronaut; and Sirhan, Amber’s son, who finds his destiny linked to the fate of all of humanity. For something is systematically dismantling the nine planets of the solar system. Something beyond human comprehension. Something that has no use for biological life in any form...

Drawing Futures brings together international designers and artists for speculations in contemporary drawing for art and architecture.Despite numerous developments in technological manufacture and computational design that provide new grounds for designers, the act of drawing still plays a central role as a vehicle for speculation. There is a rich and long history of drawing tied to innovations in technology as well as to revolutions in our philosophical understanding of the world. In reflection of a society now underpinned by computational networks and interfaces allowing hitherto unprecedented views of the world, the changing status of the drawing and its representation as a political act demands a platform for reflection and innovation. Drawing Futures will present a compendium of projects, writings and interviews that critically reassess the act of drawing and where its future may lie.Drawing Futures focuses on the discussion of how the field of drawing may expand synchronously alongside technological and computational developments. The book coincides with an international conference of the same name, taking place at The Bartlett School of Architecture, UCL, in November 2016. Bringing together practitioners from many creative fields, the book discusses how drawing is changing in relation to new technologies for the production and dissemination of ideas.

State-of-the-Art Bridge and Highway Rehabilitation and Repair Methods This authoritative volume offers up-to-date guidance on the latest design techniques, repair methods, specialized software, materials, and advanced maintenance procedures for bridges and highway structures. Focusing on both traditional and nontraditional design issues, Bridge and Highway Structure Rehabilitation and Repair clarifies the most recent AASHTO bridge design codes and discusses new analytical and design methodologies, such as the application of load and resistance factor design (LRFD). A wealth of concise explanations, solved examples, and in-depth case studies are included in this comprehensive resource. COVERAGE INCLUDES: Diagnostic design and selective reconstruction Bridge failure studies and safety engineering Analytical approach to fracture and failure Load and resistance factor rating (LRFR) and redesign Application of LRFD and LRFR methods Inspection and structural health monitoring Bridge widening and replacement strategies Conventional repair methods Advanced repair methods Concrete repair methods Extreme events of flood scour and countermeasures design Guidelines for seismic design and retrofit methods