Geotextile Applied to Old Asphalt Pavement Strengthening
Date:2014-07-26   Viewers:   Size: 16px  14px  12px

geotextile treat road crack

Geotextile Applied to Old Asphalt Pavement Strengthening

Abstract :A sheet of special geotextile laid between the old asphalt pavement and the strengthening layer can greatly decelerate reflective cracking and extend the service life of the pavement , which is proved an economical and effective way to strengthen old pavements .

Key Words:asphalt pavement ;crack prevention;geotextile

1.Preface
There will be different degrees of cracks, such as transverse joints, longitudinal seam and crack net on asphalt pavement due to long-term use and heavy traffic load.Also nature factors such as weather and temperature will cause this problem.

Crack is the most common type of asphalt pavement damage phenomenon, if the road is not timely remediation, rain and other pollutants will come into the roadbed along the gap which may cause the roadbed subsidence, than cracks increase.

Crack will cause serious damage to the pavement structure and impact of road traffic capacity and service life. How to mitigate reflective cracking is an issue of common concern to many road engineers.

The traditional prevention approach is to design the road thick enough, it has been proved that when the thickness of reinforcing layer more than 6cm, the anti-crack effect will greatly increase. Due to the high cost of this method, it is not wildly used..

In recent years. With the development and application of new materials, new technology, many domestic and foreign research proved that the use of geotextile is dedicated to slow reflective cracking of asphalt overlay is an effective, economical and practical method.

This article use Hongkong Road in Qingdao as a example. As a major traffic artery road of Qingdao.There are a lot of cracks on the Hong Kong original asphalt road , mainly due to fatigue cracking in the pavement of heavy traffic loads, followed by cracks due to temperature changes (low temperature cracking).

Pavement Cracks serious impact Hong Kong’s road capacity . How to remediate of the existing asphalt pavement cracks, has become a key issue in Hong Kong road reconstruction project.

The asphalt-soaked geotextile sandwich can effectively slow reflective cracking, it will also prevent rainwater infiltration along cracks grass. So the old road in Hong Kong road reconstruction project, we wisely chose geotextile.

2. Mechanism of geotextile reflective cracking prevention
To ensure the project quality,we choose 140g/m2 polyster filament nonwoven geotextile.This kind of geotextile features high modular,chemical and biological stable.

The GTM polyster filament non woven geotextile tensile strength reached 8kN / m or more. With good ductility and resistance to puncture and bursting capability.Stress can be extended to a wider range by using geotextiles.Geotextile play a role of energy absorption.

Because of GTM geotextile, the bonding force was greatly reduced between the overcoat layer and the old asphalt pavement, although the interface strength is lowered, but it is sufficient to prevent relative vertical displacement of the interface.

Secondly, the geotextile has excellent anti high temperature performance, the temperatures of laying asphalt will be up to 150 ℃. GTM geotextile should not melt or soften at the temperature, otherwise it will not achieve the desired effect.

Geotextile use polyester as raw material, whose melting point up to 230 ℃, so the size and performance of gtm geotextile will keep stable.
It has a good combination performance between geotextile and asphalt,asphalt rubber oil.

The normal construction step is spray glue oil first, then laying geotextile, then on which put asphalt paving then compact.

The asphalt rubber oil will come through the geotextile and combine with the asphalt layer.So the gtm geotextile must has excellent permeability.

3.Geotextile performance indicators
The geotextile can be paved by machine and man power.
GTM Geotextile has unique single-sided singeing process, so that the geotextile can not be brought up by paving vehicle tires in construction.
Mass weight 140g/m2
Thickness 1.95mm
Tensile Strength CD:400N/5cm; CMD:280N/5cm
Elongation CD:60%; CMD:65%
Melting Point 230℃~ 240℃

4.Geotextile fabric construction technology
As a new material,geotextile has a unique construction technology, construction procedures are as follows:
1.Clear the asphalt pavement , it is better using high-pressure water to clear.
2.Use tar sands to repair the old seam split, pits.
3.Spraying asphalt oil on a clean old asphalt,the amount is about 1.2kg / m2
4. The temperature should be controlled at about 160 ℃, the amount should not be too much, otherwise it will cause road weeping.
5.Lay the gtm geotextile.fix the end of the geotextile roll.Then stretch geotextile using man power or machine.Keep the elongation at 1.0%~ 1.5%. Geotextile paving should be flat, not folded
Stack of wrinkled, the interface can overlap each other at least 15cm.
6. Paving 4cm uniform medium-grained asphalt concrete on geotextile then compress it.

5.Conclusion
The use of geotextile to treat crack has got ideal effect.It is visible that laying a geotextile layer between the old asphalt road and the overlay has got great success.Compare to the traditional method to treat reflect crack,using gtm geotextile fabric will improve the road performance,saving cost and time.

 

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