Table of Contents
Why is elastic recovery important?
Elastic Recovery (ER) is used by many highway agencies for modified bitumen grading specifications. The current ASTM/AASHTO standards for ER testing utilize the ductility bath as the measurement apparatus. The results show a good correlation between the ER-DSR and ER measured in the ductility bath (ER-DB).
What is elastic recovery of bitumen?
The elastic recovery of a bitumen is expressed as a percentage of the distance between the ends of the half-threads, which has developed 30 min after the division relative to the elongation length of 200 mm.
Why and what are the additives used to modify bitumen?
Additives are substances that can be added to the bitumen binder to modify bitumen characteristics and thereby to improve workability, the adhesion to aggregate, and the properties of final asphalt mixture.
Why is bitumen modified?
Benefits of bitumen modification quickly absorbs thermal and mechanical stresses in asphalt layers of the pavement; resistant to fatigue loads due to temperature variations; wide plasticity interval and wider service temperature interval; better mechanical properties and hardness.
What is elastic recovery in textiles?
Elastic recovery: elastic recovery of a fabric is the ability to return in its original size and shape when the fabric comes under breaking load condition.
What is the function of elastic recovery in bending?
Springback or elastic recovery refers to the shape discrepancy between the fully loaded and unloaded configurations. Springback causes changes in shape and dimensions that can create major problems in the assembly.
What is elastic recovery test of bitumen?
The elastic recovery is measured by the percentage to which the asphalt cement residue will recover its original length after it has been elongated to a specific distance at a specified rate of speed and then cut in half.
What is elastic recovery?
Elastic recovery, or resilience, is a measure of the ability of an elastomer to return to its original shape when a compression load is removed.
What are the additives used to modify bitumen?
What are the Types of Modifier in Bitumen?
| TYPE OF MODIFIER | TYPE OF ADDITIVE |
|---|---|
| Antioxidants | Amines Phenols Organo-zinc/organo-lead compounds |
| Natural asphalts | Trinidad Lake Asphalt (TLA) Gilsonite Rock asphalt |
| Fillers | Carbon black Hydrated lime Lime Fly ash |
| Extender | Sulphur |
What is the reason why bitumen is used in road construction?
Asphalt bitumen is a binding organic material made from the by-products of refined crude oil. It is used in road construction because it is easy to produce, reusable, non-toxic, and a strong binder.
What is the problem with bitumen?
According to research, because of its visco-elastic behaviour bitumen has a big influence on asphalt road performance criteria. These are mainly permanent deformation, stiffness, low temperature cracking, fatigue cracking and adhesion.
Why is elastic deformation reversible?
Elastic deformation alters the shape of a material upon the application of a force within its elastic limit. This physical property ensures that elastic materials will regain their original dimensions following the release of the applied load. Here deformation is reversible and non-permanent.