UNIVERSITY OF TRANSPORT AND COMMUNICATIONS - CAMPUS IN HO CHI MINH CITY

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Smart Materials for pavement construction

There are a number of smart materials which can be characterized as 'smart' and are used for pavement construction. For instance, Self-Healing material, Nano Materials, Bacterial Concrete….
Smart Materials for pavement construction

I.  Self-Healing Materials
Currently, most industrial materials rely entirely on passive protection mechanisms; which are readily applicable and universal for different materials systems. However, they will always stay passive, and, therefore, their lifetime and functionality are limited and related to the number of protective additives and the intensity of their consumption. So, better, and preferentially active process for the protection/repair of damaged materials self-repairing processes were developed, and which need to be developed further. Although it sounds futuristic and which also affects the directions of research; self-healing of material systems already exists in all sorts of systems of materials or functionalities. Self-healing is an intrinsic property of bitumen. This technology helps in the conservation of material resources since the usual over-design of materials is no longer required. The major objective of the self-healing pavement technique is to develop a smart bituminous pavement that can assess, anticipate and heal by itself in time, without any human intervention, and substantially return to its original state. For this, the following areas are needed to be explored and studied:

Paving SMA
Paving SMA
  1. Development of multiple healing processes which are sufficient for the complete design life.

  2. To develop a mechanism that initiates/stimulates the healing action on demand.

  3. To develop a method to quantify the success of self-healing action.

The development of such areas requires interdisciplinary approach to understand the complexity of the technique and will have great future, especially for roads with limited access, and in areas where maintenance of the pavement causes hindrance/cost/disturbance to traffic flow. This will truly revolutionize the pavement materials and its design in the future

II. NanoMaterials
The clay nano-particles are the primary materials applied in asphalt construction. Adding nano-particles like nano clay, nano-silica, and nanotubes in asphalts normally increase the viscosity of asphalt binders and improves the rutting and fatigue resistance of asphalt mixtures. Using nano clay as the second modifier in polymer-modified asphalts can improve the storage stability and the aging resistance of polymer-modified asphalts. Various Atomic Force Microscopy (AFM) techniques (e.g. tapping mode imaging, force spectroscopy, and nano-indentation), as well as X-ray diffraction (XRD) experiments, can be conducted on modified asphalt binders to characterize the micro or nano-scale structures of nano-asphalts. Through the reasonable selection of nano-materials used in asphalt, nano-modified asphalt can offer many benefits in cold regions.



III. Bacterial Concrete
Today, use of technology has taken the standards of construction to a new, high level. Different types of procedures, methods and materials are used to attain a very good, sustainable and economic concrete construction. The process of self-healing of cracks or self-filling up of cracks due to bacterial reaction in the concrete after hardening is known as Self-Healing Concrete. It can be observed that small cracks that occur in a structure of width in the range of 0.05 to 0.1mm get completely sealed in repetitive dry and wet cycles. The mechanism of this autogenous healing is the width of 0.05-0.1mm that act as capillary and the water particles seep through the cracks. These water particles hydrate the non or partial reacted cement and the cement expands, which in turn fills the crack. The bacteria used for self-healing of cracks are acid-producing bacteria. These types of bacteria can be in dormant cell and be viable for over 200 years under dry conditions; they act as a catalyst in the healing process of cracks.

 

Source: https://www.nbmcw.com/tech-articles/roads-and-pavements/39680-smart-pavement-materials-and-emerging-technologies.html
Editor: Le Van Phuc


 

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