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pothole rapid

A Revolutionising Pothole Repair Material

The pothole crisis on UK roads is growing,

and it is time to find a solution.

The Science



Black Gold 15 was analysed to assess its suitability for the repair of damaged road surfaces.  Performance data collected included resistance to permanent deformation, Indirect Tensile Strength Modulus (ITSM) and Polished Stone Value (PSV). Black Gold 15 was also compared against a competitor material. 

Resistance to Permanent Deformation

Every road surface develops permanent deformation over time known are 'rutting'. Rutting appears as longitudinal depressions on the road surface and is caused by both consolidation and lateral movement along the wheel path of the road.


There are a variety of elements that cause rutting on road surfaces, but one of the key factors that have been identified is changes in temperatures. When the road surface increases in temperature, the depth of the rut increases considerably. Other major stress factors including vehicle weight, traffic volumes and speed, affect road surfacing and repairs.


Determination of Resistance to Permanent Deformation of bituminous materials or Alternative Reinstatement Materials (ARM) in accordance with BS EN 12697-22:2020 Procedure A in Air. — Test methods Part 22: Wheel tracking. 


This test is performed to gauge the vulnerability of bituminous materials or ARM to deformation, specifically that related to bearing load. To conduct this test, specimens are held in a mould and the surface is then exposed to a set number of passes of a loaded wheel at a constant temperature. The rut damage present on the surface is then assessed, determining the material's susceptibility to deform in this way.


Indirect Tensile Strength Modulus is a European standard that classifies the stiffness of bituminous mixtures using specific tests, including direct tensile tests, indirect tensile tests and bending tests. The tests are conducted by exposing compacted bituminous materials to sinusoidal loading, using a variety of sands as specimen supports. These procedures are used as a ranking system for bituminous mixtures, based on a number of characteristics:

•  Stiffness

•  Relative performance in the pavement

•  Structural behaviour


The tests are designed to judge data according to specifications for bituminous mixtures in accordance with European standards and requirements, with the outcome determining the mixture's resistance to fatigue-related damage.


Establishing the stiffness modulus is a factor of utmost necessity as it directly affects the performance of an asphalt pavement's stiffness and its ability to resist deformation in response to a controlled applied force. Should the stiffness modulus value decrease, the ageing of the asphalt will increase, resulting in cracks and damage when receiving a heavy load. An asphalt material with a higher stiffness modulus will perform more efficiently, with more resistance to bending. Stiffness modulus is considerably impacted by heat and substrate temperatures, with a higher temperature resulting in a notably lower stiffness modulus, meaning the asphalt surface repair is more susceptible to deformation, cracking and rutting over a period of time.


The following test results are specific to the wearing aggregate used in Black Gold 15

Attention to key properties such as Polished Stone Value (PSV) is warranted where safety is concerned. Properties such as size, shape and strength are also important and aids in the selection of the appropriate aggregate.


Polished Stone Value (PSV)  

PSV is a measurement of the ability of the aggregate employed in the reinstatement material to resist polishing through continuous trafficking.  The more resistant an aggregate is to polishing the higher the skid resistance.

Polished Stone Value (PSV) was tested to BS EN 1097-8 = 68

Los Angeles Coefficient (LAC)

Aggregate used in repairs and resurfacing are subjected to wearing due to traffic movement. This method tests the aggregate hardness and its ability to resist crushing and disintegration.  

Values of 30 or less are acceptable. Los Angeles Coefficient (LAC) = 30


Aggregate Abrasion Value (AAV)

This test indicates the abrasive quality of an aggregate. The lower the figure the more resistant to wearing. Values of 16 or less are acceptable. Aggregate Abrasion Value (AAV) = 1.1 Aggregate Impact Value (AIV) AIV test results indicate the aggregates resistance to impact stress due to traffic.  Standard values for AIV are as follows: 10% extremely strong, 11 -20 strong, 21 -30 acceptable. Figures above 35 are considered unsuitable.

Aggregate Impact Value (AIV) =19


In regards to the resistance to rutting: The Black Gold 15 sample considerably outperformed the tested competitor in this field. Results show that Black Gold 15 displayed a rutting figure of just 0.6mm - significantly lower than that of the competitor material.


The Indirect Tensile Strength Modulus test results are particularly compelling since the stiffness modulus figures represent a considerable difference between the two materials with nearly a 3 fold difference. Black Gold 15 also outperforms the competitor with significantly higher results in both horizontal stress and vertical force displaying further evidence of its superior resistance to cracking, deformation and more endurance when exposed to higher temperatures.  


Other factors including LAC, AAV and AIV values all confirm Blackgold 15 as an excellent high quality repair for car parks, roads and highways and an excellent repair choice overall. 

We are dedicated to supporting local authorities, transportation agencies, and construction professionals in their efforts to build and maintain roads that meet the highest standards of durability, safety,

and environmental responsibility. Together, we can put an end to the UK's pothole crisis.

Contact us for more information about how our solution can revolutionise road repair and contribute to a sustainable infrastructure.

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