بایگانی برچسب برای: Asphalt

Asphalt.Materials.and.Mix.Design.Manual.Irving.Kett.[taliem.ir]

ASPHALT MATERIALS AND MIX DESIGN MANUAL

The purpose of the Manual for Asphalt Materials and Mix Design (hereafter referred to as The MANUAL) is to familiarize students with the technology of asphalt in its several forms namely asphalt cement, cutback asphalt, and asphalt emulsions. The laboratory work is designed to develop an understanding of asphalt properties, characteristics, testing procedures, and specifications. For engineering purposes three properties of asphalt are paramount: consistency (usually referred to as viscosity), purity, and safety. Before asphalt cement can be used for construction purposes it must be liquefied. This implies heating. Asphalt cement must be liquefied before it can be pumped through pipes, mixed with aggregates to make asphalt concrete, or sprayed through nozzles. Once the heat is dissipated, the asphalt cement reverts to its amorphous, semi- solid state. There are other ways to liquefy asphalt. Selected petroleum based solvents can dissolve the asphalt cement to create a family of materials known as cutback asphalts. Another method is to combine asphalt cement with water in the presence of a catalyst to form various kinds of asphalt emulsions. The procedures outlined herein are all derived from ASTM designations and practice as recommended by the Asphalt Institute. Where the particular ASTM method permits alternate rocedures, the one more applicable to the available equipment and the teaching situation was chosen. In the preparation of this MANUAL, the inherent time constraints of an academic laboratory was considered, whenever possible.
Recycling of waste tire rubber in asphalt and portland cement concrete[taliem.ir]

Recycling of waste tire rubber in asphalt and portland cement concrete: An overview

Waste tires pose significant health and environmental concerns if not recycled and/or discarded properly. Over the years, recycling waste tires into civil engineering applications, especially into asphalt paving mixtures and portland cement concrete, has been gaining more and more interests. This review summarizes the recent advances in the use of waste tire rubber in asphalt and portland cement concrete. The use of crumb rubber in asphalt paving mixture has long been proven successful due to good compatibility and interaction between rubber particles and asphalt binder, leading to various improved properties and performance of asphalt mixtures. The rubberized asphalt mixtures also have shown good compatibility with two widely used sustainability technologies in asphalt paving industry – reclaimed asphalt pavement (RAP) and warm-mix asphalt (WMA). In comparison with its use in asphalt paving mixtures, recycling of waste rubber in Portland cement concrete has not been so successful due to two factors: (1) incompatibility in chemical property between rubber and cement paste and (2) the significant difference in stiffness resulting in stress concentrations. Various methods have been proposed to overcome the barriers to improve the performance of rubberized portland cement concrete, some of which have shown to be promising.
Recycling of waste tire rubber in asphalt and portland cement concrete[taliem.ir]

Recycling of waste tire rubber in asphalt and portland cement concrete: An overview

Waste tires pose significant health and environmental concerns if not recycled and/or discarded properly. Over the years, recycling waste tires into civil engineering applications, especially into asphalt paving mixtures and portland cement concrete, has been gaining more and more interests. This review summarizes the recent advances in the use of waste tire rubber in asphalt and portland cement concrete. The use of crumb rubber in asphalt paving mixture has long been proven successful due to good compatibility and interaction between rubber particles and asphalt binder, leading to various improved properties and performance of asphalt mixtures. The rubberized asphalt mixtures also have shown good compatibility with two widely used sustainability technologies in asphalt paving industry – reclaimed asphalt pavement (RAP) and warm-mix asphalt (WMA). In comparison with its use in asphalt paving mixtures, recycling of waste rubber in Portland cement concrete has not been so successful due to two factors: (1) incompatibility in chemical property between rubber and cement paste and (2) the significant difference in stiffness resulting in stress concentrations. Various methods have been proposed to overcome the barriers to improve the performance of rubberized portland cement concrete, some of which have shown to be promising