Buy ASTM D() Test Method for Coating and Stripping of Bitumen- Aggregate Mixtures from SAI Global. Standard Method of Test for. Coating and Stripping of Bitumen-Aggregate Mixtures AASHTO Designation: T () ASTM Designation. ASTM D Coating and Stripping of Bitumen-Aggregate Mixtures_建筑/ 土木_工程科技_专业资料。美国材料试验标准,水浸法沥青剥落试验.
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This document discusses how anti-stripping agents can eliminate the possibility of some instabilities in asphalt, such as crumbling and the formation of holes. Many developments in the past 50 years have improved the performances of bituminous mixtures and allowed the recycling of more materials coming from the demolition of old pavements.
NORMA ASTM D 1664-80
This, happily, leads to a reduction of environmental impact through less use of non-renewable first-use raw material. What is often unconsidered is the importance of bitumen-aggregate adhesion which is independent from any polymer modification performed.
Better adhesion between aggregates and bitumen can be ensured through the usage of anti-stripping agents. One of the main triggers of pavement deterioration is the weakening or the detachment of the bitumen film adhering to the surface of the aggregate stripping.
World Highways – The role of anti-stripping agents in asphalt performance
In detail, the factors that affect stripping  are:. As soon as the bitumen film separates, the pavement immediately starts to deteriorate. Typical deteriorations caused by this stripping are: The adhesion of bituminous binders involves physical properties of different origin.
The adhesion is influenced by the characteristics of both the bitumen hydrophobic material and the aggregate used in the mixture basically hydrophilic material. Other factors are the environmental conditions humidity and temperaturesurface characteristics of the pavement qstm, porosity and coating and vehicular movements upon the pavement. Adhesion can be defined generally as the molecular force of attraction between two bodies of different nature in contact with each other.
In the context wstm the asphalt concrete, the contact is liquid bitumen and solid aggregates. With the mixing between aggregates with bitumen, the latter covers the aggregates . The bituminous binder creates a superficial film around the aggregate in order to obtain a hydrophobic surface, actually impermeable to the particles of water figure 1.
NORMA ASTM D – Free Download PDF
The main theories of adhesion [1,4,5] developed over the years have been: With reference to the surface energy theory, the last resistances before internal cracking in the binder film cohesion are within the binder-aggregate interface adhesion.
Therefore, adhesion and cohesion have a key role in determining the durability of flexible road pavements. Stripping occurs when the binder has a greater internal cohesion than the adhesion with the aggregate, resulting in the detachment of the bitumen film from the aggregate.
Instead, considering the chemical adhesion theory, the molecular interactions in the maltenic fraction of the bitumen have crucial importance that depends on : D664 time there is a separation of the bitumen layer from the stone surface, there is the interposition of water and a direct reduction in performances of the asphalt concrete. Various studies have shown that water-proofing of pavement is the best solution. The situation is guaranteed both through the correct mix design of awtm laboratory mixtures and through the use of the necessary anti-stripping agents .
If it is not possible to alter the nature of the aggregate constituting the bituminous mixtures, the only controllable factor is the bitumen, through the use of anti-stripping agents.
Anti-stripping agents are chemical mixtures containing active functional groups that improve the adhesion of the bitumen film on the surface of the aggregates. Mixed with the binder, they lower the surface tension of the bitumen figures 2 and 3. There are different types of anti-stripping amino, asrm or silane.
Choosing one over the other depends substantially on the chemical nature of the aggregates used. Since the bitumen is acidic in nature, we have that: These correspondences are generated by the chemical actions that take place. For example, the amino portion contributes to improving the adhesive properties. Being basic, the amine additives work better with acid aggregates, where the adhesive power is due partially to the action performed by opposite charges. The additives also contain functional groups that affect dispersion and the peptisation of the constituents of asphaltene type, with consequent changes as regards cohesive forces .
The role of anti-stripping agents in asphalt performance
Some of the tests mostly used for the verification of the stripping are: Since there is a close correlation between the sensitivity to moisture and aastm degradation of its mechanical properties such as stiffness modulus and resistance to fatigueother tests are performed to verify the change in the mechanical properties of the bituminous mixture : Advertise Site map Contact us.
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In detail, the factors that affect stripping  are: Aggregates bitumen without anti-stripping agent after Boiling Test. There has been a lot of research and published case histories regarding stripping and the use of anti-stripping agents. Adhesion types The adhesion of bituminous binders involves physical properties of different origin. Figure 3 Aggregates bitumen with anti-stripping agent, after Boiling Test. Astj of the change of the indirect tensile strength ITSR is definitely one of the simplest, faster and more used tests.
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