Measurement of depth, identification of material and air void content

Core samples are taken from reinstatements or newly laid footways and carriageways, delivered to our  UKAS accredited testing laboratory for the following areas of compliance:

Core depth and material compliance

Measuring the depth of a core is a key part of the testing. If the reinstatement is not of the correct depth, it will not be stable or durable and will fail the SROH requirements. The SROH sets out the legal requirements for material and stone size to be used in highways and footways.

Air voids

Testing the air voids in a core shows that NRSWA legislation is being complied with and that voids are at the correct SROH specification. The presence of water in pavements is detrimental to its life. It is vital to achieve adequate compaction to keep initial permeability low and prevent increased oxidation, water damage spalling and cracking. Low air voids may cause rutting and bleeding. Air void testing also proves that materials which are designed to be porous allow water to pass through the matrix so that drainage occurs.

Core sampling and testing is the only reliable way to check the compliance of reinstatements on public highways and footways. If you want to find out more about the processes that we follow please click here

Drying the core samples we use InstroTek’s CoreDry which uses vacuum technology to rapidly and completely dry compacted asphalt samples within minutes without degrading or changing the samples properties. It produces the most accurate and repeatable dry sample weight.

Core sampling and testing BS EN standards for which Trench Right has UKAS accreditation

  • Coring of materials laid (Sampling laid and compacted materials by coring BSEN 12697-27:2017)
  • Core Depth Check (Determination of the thickness of a bituminous pavement. BS EN 12697-36:2003). Following guidance from the Specification of the Reinstatement of Openings in Highways (SROH)
  • Bulk Density (Procedure C Sealed specimen BS EN 12697-6:2020)
  • Maximum Density (Procedure A : Volumetric BS EN 12697-5:2018)
  • Air Voids Content (BS EN 12697-8:2018)

 

Core samples in the incubator during the bulk density procedure it maintains a constant level of dryness

We are completely impartial, independent and transparent we guarantee that the client receives accurate, factual results with traceability from our testing service.

At Trench Right, we are committed to using the latest IT technology.

We use data capture software on mobile devices which enables our engineers to collect data immediately upon inspection which increases data validity.

By logging into the client secure database you can access the following;

  • Location including GPS co-ordinates and mapping
  • Site photographs
  • Core samples taken
  • Certificates of results
  • Performance reports and charts
Why is there a need to core sample

Core Sampling and Testing is the only reliable way to check the compliance of reinstatements. Primary legislation linked to ‘The New Roads and Street works Act 1991 (NRSWA) which imposes a duty on them to reinstate the road on completion of their works to meet standards as set out in the statutory code of practice (Specification for the Reinstatement of Openings in Highways).

Why is there a need to air void test

The presence of water in a pavements is detrimental to its life.

It is vital to achieve adequate compaction to keep initial permeability low and prevent increased oxidation, water damage spalling and cracking.

Low air voids may cause rutting and bleeding. Air void testing also proves that materials which are designed to be porous allow water to pass through the matrix so that drainage occurs.

How many core sites should be sampled

The total volume will be dependent on the level of compliance from the undertaker.

This will be discussed between the Local  Authorities and Utilities with a 10% starting point rising up to 80% if continuous failures are found.