Modeling and Design of Flexible Pavements and Materials

Modeling and Design of Flexible Pavements and Materials
Author: Dallas N. Little
Publisher: Springer
Total Pages: 702
Release: 2017-09-25
Genre: Technology & Engineering
ISBN: 331958443X

This textbook lays out the state of the art for modeling of asphalt concrete as the major structural component of flexible pavements. The text adopts a pedagogy in which a scientific approach, based on materials science and continuum mechanics, predicts the performance of any configuration of flexible roadways subjected to cyclic loadings. The authors incorporate state-of the-art computational mechanics to predict the evolution of material properties, stresses and strains, and roadway deterioration. Designed specifically for both students and practitioners, the book presents fundamentally complex concepts in a clear and concise way that aids the roadway design community to assimilate the tools for designing sustainable roadways using both traditional and innovative technologies.

Physical and Chemical Properties of Cement and Aggregate in Concrete

Physical and Chemical Properties of Cement and Aggregate in Concrete
Author: National Research Council (U.S.). Highway Research Board
Publisher:
Total Pages: 82
Release: 1960
Genre: Aggregates (Building materials)
ISBN:

Paper 1: The pore-size distribution present in some carbonate rocks was determined as part of an investigation concerned with the properties of aggregate which affect the durability of portland cement concrete. Paper 2: 52 concrete aggregates were evaluated by means of the rapid chemical test for potential alkali-aggregate reactivity and the results generally showed good correlation with the data obtained in the mortar bar tests. Paper 3: It is demonstrated that the types of carbonate aggregate from the cedar valley formation in Iowa which have been classed as acceptable or unacceptable on the basis of service records, can also be differentiated on the basis of their reactivity with silica and/or fluoride in aqueous solution. Paper 4: Mixtures of calcium hydroxide, pozzolan, and water were reacted at 100 F for 1 to 6 months, and the reaction products were examined by x-ray diffraction and thermal analysis.

Chemical Reactions

Chemical Reactions
Author: W. Lerch
Publisher:
Total Pages: 12
Release: 1956
Genre: Concrete
ISBN:

The bond between the aggregate and the matrix has a significant effect on the strength, permeability, and durability of concrete. It is probable that the bond is affected by chemical reactions at the surface of the aggregate and by the surface texture or other characteristics of the aggregate. There is no suitable direct method available for measuring this bond between the aggregate and the matrix. The strengths obtained in testing the mortar-making properties of fine aggregates (ASTM Method C 87), the compressive strength of concrete cylinders (ASTM Method C 39), and the flexural strength of concrete (ASTM Method C 78), and visual observations made in connection with these tests provide some information about the bond. High strengths are an indication of a good bond. When it is observed that breaks occur through the aggregate, there is evidence of good bond. When the break occurs around the aggregates and they can be pulled out of their sockets, a poor bond is indicated. The entire problem of the chemical and physical factors that influence the bond between aggregate and matrix is one that deserves further study.

Soil as World Heritage

Soil as World Heritage
Author: David Dent
Publisher: Springer Science & Business Media
Total Pages: 489
Release: 2013-09-30
Genre: Science
ISBN: 9400761872

Soil as World Heritage celebrates a half century of field experiments on the Balti Steppe, in Moldova - where Dokuchaev first described the Typical Chernozem in 1877, protected from the elements by a unique system of shelter belts designed by the great man, and now provisionally listed as the first World Heritage Site for soil. The book presents contributions to the 2012 international symposium attended by researchers, practitioners and policy makers from the European Commission and countries as diverse as Belarus, Bulgaria, the Czech Republic, France, Germany, Italy , the Netherlands, Romania, Russia, Ukraine, United Kingdom, USA and, of course, Moldova itself. The experimental data demonstrate the damage caused by human activity to the productivity and integrity of the black earth and, also, ways to restore its fertility. Results from even longer-established trials worldwide also demonstrate that agricultural practices are driving global warming, leaching of nutrients, pollution of water resources, diversion of rainfall away from replenishment of soil and groundwater to destructive runoff, and destroying soil organic matter and biodiversity. These are pressing issues for our generation and will press harder on future generations. Long-term field experiments, and the scientific skills and experience that they nurture, will be more and more valuable as a foundation and focus for interdisciplinary teams studying the effects of farming practices on the soil and soil life so as to devise a sustainable alternative. Europe-wide and worldwide contributions also discuss economic incentives - carbon and green water credits - which themselves require robust supporting data, and legislative aspects of promoting more sustainable farming systems. The outcomes of the conference include recommendations for institutional support for sustainable farming and a draft of the law on land and soil management for the Parliament of Moldova.