Pavement repair system

Abstract

A pavement repair system is provided utilizing solid phase auto regenerative cohesion and homogenization by liquid asphalt oligopolymerization technologies. The system is suitable for use in repairing asphalt pavement, including pavement exhibiting a high degree of deterioration (as manifested in the presence of potholes, cracks, ruts, or the like) as well as pavement that has been subject to previous repair and may comprise a substantial amount of dirt and other debris (e.g., chipped road paint or other damaged or disturbed surfacing materials). A system utilizing homogenization by liquid asphalt oligopolymerization is suitable for rejuvenating or repairing aged asphalt, thereby improving properties of the paving material.

Description

INCORPORATION BY REFERENCE TO RELATED APPLICATIONS[0001]Any and all priority claims identified in the Application Data Sheet, or any correction thereto, are hereby incorporated by reference under 37 CFR 1.57. This application is a continuation of U.S. application Ser. No. 15 / 363,858, filed Nov. 29, 2016, which is a continuation of U.S. application Ser. No. 15 / 148,998, filed May 6, 2016, now U.S. Pat. No. 9,551,114, which is a continuation of U.S. application Ser. No. 14 / 702,610, filed May 1, 2015, now U.S. Pat. No. 9,347,187, which is a continuation of U.S. application Ser. No. 14 / 373,889, filed Jul. 22, 2014, now U.S. Pat. No. 9,057,163, which is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT / US2014 / 026755, filed Mar. 13, 2014, which is a continuation-in-part of U.S. application Ser. No. 13 / 842,640 filed Mar. 15, 2013, now U.S. Pat. No. 8,992,118, and which claims the benefit of U.S. Provisional Application No. 61 / 799,515 filed Mar. 15, 2013, U.S. ...

AI Technical Summary

Benefits of technology

The patent text describes a method and composition for repairing asphalt pavement that is cost-effective and results in a long-lasting surface. The composition modifies the failure mechanisms of the pavement to improve waterproofing, maintenance of microtexture, resistance to embrittlement, and resistance to mechanical stress. The text also shows that compositions can be used for rejuvenating aged asphalt to restore its paving properties. Additionally, the patent describes the use of elastomers cured with terahertz radiation for coatings, paints, structural materials, and fire-resistant coatings. The technical effects of this patent text are improved durability, flexibility, and resistance to various failure mechanisms of asphalt pavement, resulting in a longer-lasting surface.

Problems solved by technology

Repair and maintenance of the civil infrastructure, including roads and highways of the United States present great technical and financial challenges.

The result is a rapidly failing infrastructure.

It begins to lose its integrity on the surface, causing aggregate at the surface of the pavement to be lost.

The pavement surface roughens as aggregate is lost, and cracks begin to form.

After approximately fifteen years of exposure to the elements, it becomes cost prohibitive to attempt to maintain asphalt pavement via conventional cold patching, waterproofing, and slurry techniques.

Cracks and stresses in a repaired underlying road bed will quickly imprint themselves on new overlays of paving material, due to the malleability of the new asphalt under rolling loads.

This will inhibit the rate of telegraphing of cracks to a limited extent, such that instead of taking place from 6 months to 2 years after repair, the cracks do not telegraph for from to 1 year to 3 years after repair.

After the first five years, physical symptoms of deterioration are observed, including lateral and longitudinal cracks due to shrinkage of the pavement mass through the loss of binder and embrittlement of the asphalt.

Cracks ultimately result in creation of a pothole.

A stress fracture is where the pavement, for one reason or another, may not have been thick enough to withstand exposure to an extremely heavy load, moisture, or poor compaction underneath.

When combined with shrinkage of the asphalt itself as it goes through heating and cooling cycles, and application of oxidative stress, stress fractures can also result.

In terms of the chemistry of deterioration, study data indicate that asphalt pavement fails because it becomes brittle.

Embrittlement leads to mass loss, which leads to shrinkage, which produces cracks.

Cracks become potholes, the pavement stops flexing, and aggregate becomes dislodged.

It is this “embrittlement zone” where ductility is lost and failure takes place.

Over a period of time, the asphalt goes from being flexible to becoming brittle.

Once that happens, the pavement becomes inflexible, cracks open up, the pavement loses mass, and rolling loads break up the pavement, causing cracking, potholes, running, ravelling, and block cracking, each resulting in a loss of the pavement integrity.

The conventional methods for repair of surface defects inclusive of rejuvenators and fog seals typically do not exhibit a desirable lifespan.

The primary factor is that the repairs do not remedy the underlying embrittlement of the asphalt binder deep within the pavement cross-section.

A secondary failure mechanism is loss of rock itself due to hydrolytic attack of the asphalt-rock interface.

Hydroxide groups can form upon exposure to water, resulting in oxidative reactions that impair the adhesion of asphalt to the rock surface, a process referred to as stripping.

The asphalt breaks down from exposure to heavy load and the sun, causing water to penetrate between the asphalt and rock.

Raveling occurs, resulting in a loss of macrotexture.

Ultimately, the microtexture of the surface is lost due to abrasion of tires across the surface rubbing off the asphalt and polishing the rock surface, whereby the coefficient of friction drops to unacceptable levels.

Over time, loss of microtexture and ultimately macrotexture results in the coefficient of friction dropping to below about 0.35, at which point the pavement becomes inherently unsafe in terms of steer resistance in the presence of water.

Even if a pavement surface does not have raveling or cracking, it can still be unsafe to drive on due to loss of adequate surface texture.

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