Micro-surfacing and Slurry Sealing: Road Maintenance by Paving Technology

This article explores the revolutionary nature of micro-surfacing and slurry sealing pavers which are the state of the art solutions that are reinventing the manner in which we handle and maintain our road networks. Learn how by using these advanced solutions municipalities and contractors can save key time and money and ensure a bright future of our transportation infrastructure.

Learning the Science of Road Deterioration

It is not only the one or the other heavy truck that is the main culprit but the sun and the water as well. The UV rays of the sun oxidize the asphalt binder and make it brittle, in which case hairline cracks are formed. Then water is leaking into these cracks and when it freezes and then thaws it swells forming bigger cracks and finally potholes. Traffic also increases the rate of this process by placing stress on the pavement that is weakened and causing the aggregate to loosen and ravel and form ruts in the paths of the wheels.

Otherwise, the condition of a road will degrade along a foreseeable curve. Well-maintained road may remain in good condition over a long period of time, but once it starts to deteriorate, the process will go very fast. A timely protective treatment will allow us to flatten this curve, shifting the point of failure well into the future by treating the road during the right time, or when it is in the “good” or “fair” range. This is the main idea of preventative maintenance and that is where micro-surfacing and slurry sealing can provide an excellent competitive edge.

What is micro-surfacing?

Micro-surfacing is a cold-mix polymer modified asphalt emulsion pavement system, which is high-performance. It is an accurately balanced combination of polymer-modified asphalt emulsion, mineral aggregate, water and chemical additives. In comparison to conventional hot-mix asphalt, micro-surfacing is a cold-applied method of coating, implying that it could be used without high-temperature equipment, which saves money and minimizes environmental effects.

Micro-surfacing is successful because of its superior formulation. Polymer modification of asphalt emulsion offers singly outstanding strength, pliability, and rutting and cracking resistance. The mixture is laid on a road surface where it forms readily through a chemical reaction (and not by evaporation), and may be put back into traffic within an hour or two.

Micro-surfacing is the most suitable case with roads that present:

(1)Moderate to severe rutting: It is capable of rutting to 1.5 inches deep in one pass.

(2)Oxidation and raveling: It is an offer of a new, long-lasting wearing course, which is sealing the surface.

(3)Minor/moderate cracking: The material sticks and seals cracks and does not allow the entry of water.

(4)Loss of skid resistance: The graded aggregate offers a new high-friction surface, which enhances safety.

Due to its strength and quick curing quality, micro-surfacing will be an ideal fit with big volume urban roads, arterial streets and highways. It is not a band-aid, it is a structural and functional enhancement that greatly increases the life of pavement and also makes it safer and more attractive.

What is slurry sealing?

Another related yet different method of preservation of pavement is slurry sealing. It is composed of a fine-graded aggregate, a specially made asphalt emulsion, water, and other additives. It is also a cold-applied process similar to micro-surfacing. Slurry sealing is however done with a smoother, finer aggregate and a standard asphalt emulsion.

The main role that a slurry seal plays is to serve as a barrier. It is designed to:

(1)Seal the surface: It is effective in closing the small cracks and spaces so that the water does not enter the pavement structure.

(2) Butterworth texture: It gives a fresh, smooth black texture to the surface, enhancing its aesthetics and concealing small flaws.

(3)Shield against oxidation: It provides a new coating of seal which protects the old pavement against the harmful UV rays of the sun.

(4)Enhance skid resistance: The new aggregate layer is more tractive.

Slurry sealing is considered as the best choice on roads of good to fair condition which are experiencing aging but without a major rutting or structural problem. It is a preventive measure that is used on healthy roads to maintain their condition. It is particularly common in residential streets, low-volume rural roads, and parking lots where it provides a very economical method of obtaining years of added life of the pavement.

Micro-surfacing and Slurry Sealing: Which Solution to Select?

Although both of the technologies belong to the family of cold-mix pavement preservation, their uses are determined by the road-related requirements.

The decision between the two should be based on a keen evaluation of the condition of the pavement, the number of traffic and the budget. Micro-surfacing is the more resistant, performance based system to use on more distressed roads whereas slurry sealing is the final preventative and cosmetic solution to use on roads in good shape.

The Slurry Sealing Paver: The Heart of the Operation

Any micro-surfacing or slurry sealing project depends on the accuracy and effectiveness of application apparatus. It is here that the paver will be the most important item in the puzzle.

What is a slurry sealing paver?

It is not simply a truck with a hopper. It is a very specialized, closed system machine, with the capability of ensuring precision and continuity in mixing and applying the slurry or micro-surfacing material on the road surface in a single pass.

The advance pavers are basically wheeled asphalt plants. They have built-in individual storage tanks of individual component-aggregate, emulsion, water and additives and an elaborate computerized mixing system. The technology can be used to proportion each ingredient on a fine and continuous basis as per the specifications of the mix design. This is mixed in a continuous flow, only a few seconds prior to being released to the spreading box. This on-site mixing guarantees a fresh high quality mix that does not experience premature breaking of the emulsion as experienced with traditional batch mixing.

A fine micro-surfacing paver or slurry sealing paver will also be characterized by:

1. Variable Width Spreading Box: This gives the operator the capability to change the width of the application to fit different lane widths and road shapes on the fly.
2. Automated Controls: Contemporary pavers have installed automated control systems to enable the operator to control and monitor all the mixing parameters at a single station, which ensures that there is consistency and control over quality.
3. Continuous Flow Capability: The design of the machine enables the machine to be constantly replenished with material support trucks without halting, thus creating a continuous high-speed application that will generate the minimal amount of traffic congestion.
4. Combined Agitator and Screed:The spreading box has an agitator that continuously mixes the material and a variable screed that allows it to have a perfectly smooth and even application.
5. Micro-surfacing and slurry sealing is effective due to the accuracy of this equipment.The failure of the treatment may prematurely be the result of an uneven or a mix of it. The pavers that we have are of state-of-the-art and designed to remove such risks hence giving us perfect results at all times.

The reason why advanced pavement preservation is worth investment?

Investing in micro-surfacing or slurry sealing is a strategic decision that is a good payback. The saving of money in the long term is immense.A road can be maintained at a fraction of the cost of a complete reconstruction by making the treatments at the right time. This leaves budget to be used elsewhere on important infrastructure.

In addition to the financial gains, there are important operational and environmental gains:

Reduced Traffic Interruption: Micro-surfacing and slurry seal projects can be closed and reopened to traffic much quicker than when using the conventional resurfacing and thus, minimum traffic disruption. This makes it less inconveniencing to the populace and minimizes the chances of accidents.

Environmental Sustainability: Since cold-mix procedures, those processes consume much less energy as compared to hot-mix asphalt, which necessitates heating the aggregate and binder beyond 300 degrees Fahrenheit (150 degrees Celsius). This would greatly lower the carbon emission and energy use.

Safety Improvements: The two treatments offer new surface on which the skid resistance is increased thus making the roads safer to all drivers.

Installing an extensive pavement management plan with such preventive treatments is a clever, futuristic approach of any municipality, a contractor or the owner of a property involved in the maintenance of a network of roads.

SINOTO Dedication to excellence

Our company takes a leading position in the pavement preservation industry. We do not only offer a service, we offer a solution. Our high-technology slurry sealing pavement are in good conditions so that they always perform at their best and will not breakdown at any task.

We also subscribe to the partnership with our clients, where we offer professional advice in order to make a choice in favor of a particular solution.

Get in touch with us to understand how our micro-surfacing and slurry sealing solutions can revolutionize your pavement maintenance approach and ensure the infrastructure future.