Highway Focus


Book Description




Recycling of Portland Cement Concrete Airport Pavements


Book Description

The objective of this study was to develop criteria and guidelines for recycling portland cement concrete (PCC) airport aprons. Included in this study are all aspects of the recycling process including breakup and removal, steel reinforcement removal, crushing, screening, stockpiling, mix design, testing, placing, finishing, and performance. Recycling of PCC requires some specialized equipment such as pavement breakers and electromagnets for steel removal; however, all of the other equipment and procedures are those commonly used in the construction industry. Based on the regression experimental design procedure and laboratory tests conducted on pavement samples from six airports of widely varying age and conditions, it has been conclusively shown that aged PCC pavements can be recycled into new surface courses that meet strength requirements and have the same cyclic load carrying (fatigue) characteristics as those constructed with virgin sand content - 42 percent.




Recycling of Portland Cement Concrete Roads in Iowa


Book Description

We are depleting the once seemingly endless supply of aggregate available for concrete paving in Iowa. At the present time, some parts of our state do not have locally available aggregates of acceptable quality for portland cement concrete paving. This necessitates lengthy truck and rail hauls which frequently more than doubles the price of aggregate. In some parts of the state, the only coarse aggregates available locally are "d-cracking" in nature. Iowa's recycling projects were devised to alleviate the shortage of aggregates wherever they were found to have an economic advantage. We completed our first recycling project in 1976 on a 1.4 project in Lyon county. The data collected in this project was used to schedule two additional projects in 1977. The larger of these two projects is located in Page and Taylor county on Highway #2 and is approximately 15 miles in length. This material is to be crushed and re-used in the concrete paving, it is to be reconstructed on approximately the same alignment. The second project is part of the construction of Interstate I-680 north of council Bluffs where an existing 24 foot portland cement concrete roadway is to be recycled and used as the aggregate in the slip form econocrete subbase and the portland cement concrete shoulders.




Recycling of Portland Cement Concrete Pavements


Book Description

This synthesis will be of interest to pavement designers, construction engineers, and others interested in economical methods for recontstructing portland cement concrete (PCC) pavements. Information is provided on the processes and procedures used by a number of states in using PCC pavement as aggregate in reconstructed concrete pavement. Since 1975 a number of state highway agencies have reconstructed concrete pavements using the old PCC as aggregate in the new pavement. This report of the Transportation Research Board describes the processes used on various projects in several states, giving details of construction procedures, as well as test results on various properties of the recycled aggregates and the resultant concrete.




Sustainable Construction Materials


Book Description

Sustainable Construction Materials: Recycled Aggregate focuses on the massive systematic need that is necessary to encourage the uptake of recycled and secondary materials (RSM) in the construction industry. This book is the fifth and the last of the series on sustainable construction materials and like the previous four, it is also different to the norm. Its uniqueness lies in using the newly developed, Analytical Systemisation Method, in building the data-matrix sourced from 1413 publications, contributed by 2213 authors from 965 institutions in 67 countries, from 1977 to 2018, on the subject of recycled aggregate as a construction material, and systematically analysing, evaluating and modelling this information for use of the material as an aggregate concrete and mortar, geotechnics and road pavement applications. Environmental issues, case studies and standards are also discussed. The work establishes what is already known and can be used to further progress the use of sustainable construction materials. It can also help to avoid repetitive research and save valuable resources. The book is structured in an incisive and easy to digest manner and is particularly suited for researchers, academics, design engineers, specifiers, contractors, and government bodies dealing with construction works. - Provides an exhaustive and comprehensively organized list of globally-based published literature spanning 5000 references - Offers an analysis, evaluation, repackaging and modeling of existing knowledge that encourages more responsible use of waste materials - Provides a wealth of knowledge for use in many sectors relating to the construction profession, including academia, research, practice and adoption of RSM




Transportation


Book Description




Adhesion Problems in the Recycling of Concrete


Book Description

The building explosion during the years 1945-1960 will inevitably lead to increased demolition in the next decades since the lifetime distribution of structures no longer fulfills its functional social requirements in an acceptable way. In the building period mentioned there was a great increase in reinforced and prestressed concrete construction. Consequently there is now more and more concrete to be demolished. Increasingly severe demands will be made upon demolition technology, including the demand for human- and environment-friendly techniques. On the other hand, the possibility of disposing of debris by dumping is steadily diminishing, especially close to major cities and generally in countries with a high population density. At the same time in such countries and in such urban areas a shortage of aggregates for making concrete will develop as a result of restrictions on aggregate working because of its effect on the environment and because of the unavailability of aggregate deposits due to urban development. From the foregoing it follows that recycling and re-use of environment- and human-friendly demolished and fragmented building rubble should be considered. The translation of this general problem into terms of materials science is possible by forming clear ideas of adhesion and cohesion: the whole process of demolition, fragmentation, and recycling or re-use of concrete is to break the bonding forces between atoms and molecules and to form new bonds across the interfaces of various particles of either the same nature or a different nature.




Recycling Materials for Highways


Book Description

"This synthesis will be of special interest and usefulness to design engineers, materials technologists, and others seeking information on the potential use of recycled materials in design, construction, rehabilitation, and maintenance of pavements, bases, and other components of the highway system. Detailed information is presented on procedures for pavement recycling."--Avant-propos.