Dr.Vilas Deshmukh
Sunday, April 19, 2009
MODIFIED WHITE TOPPING
White topping was developed as an effective solution for the repair and strengthening of damaged bituminous roads. The assumptions that are made while designing these white toppings are that a part of the bituminous layer is milled and removed and on the rough surface so created an unbounded layer of concrete is laid with a thickness ranging between 190 mm to 250 mm.
The white topped concrete surface are cut into panel sizes of 3.5 metre x 4.5 metre. Although it provides a cheaper solution than a new concrete road, the thickness of white topping is the controlling factor in determining the cost. This resulted in a technical solution which was more expensive than the bituminous strengthening and resurfacing layer by a factor of 5 times or more.
In addition, there are some other factors also which contribute to the solution being not very popular. The curing period is minimum 28 days for the concrete to attain the required flexural strength of 4.5 MPa. This time period of construction keeps the road blocked for a long time.
To overcome these disadvantages the DENSEN Technologies Group made innovative modifications in the conventional white topping technology to overcome these fatal flaws. The Ultra Thin White Topping technology developed by DENSEN has the following important features:
1. Cost reduction : This was done by improving the flexural strength of the concrete and bonding the concrete to the existing bituminous layer.
2. Fast track construction Developing suitable compressive strength and flexural strength to allow traffic to be opened in 72 hours as against upto 28 days
3. Easy Placement Designing the placement technology to allow proper vibration for a dense concrete layer. The technology developed is self compacting concrete.
The technologies incorporated are :
Self compacting concrete
Ultra thin white topping
Liquid hydration inhibitor
Bonding methodology of white topping
Develop requisite properties to allow traffic to be opened on the concrete roads within 72 hours
The benefits of Ultra thin white topping:
Existing asphalt pavement is repaired and strengthened
Pot holes are eliminated
Improved skid resistance
Improved life
Minimal traffic disturbance
No maintenance
No damage with water