Testing

Road Quality Testing

Asphalt Road Quality Testing
Road Quality Testing is essential in producing quality asphalt roads and prolonging their usage life. Quality testing is an essential factor in the producing quality road surfaces and developing new methods for improving driving factors, such as durability and wear characteristics, as well as road surface properties including wear patterns and grip and traction. Road quality testing provides vital information for making data-backed decisions on improving road use and wear characteristics. The equipment presented in the road quality testing section of our Asphalt testing equipment section is used to determine the quality of the actual road surface.

Performance testing is a crucial part of the asphalt QC/QA process, ensuring that the finished pavement meets the standards for durability and performance outlined in standards developed by State and Federal agencies. QC/QA tests include a variety of tests to evaluate different characteristics predicting how an asphalt mixture will behave under specific conditions. Performance testing is useful in the product development stage of asphalt additives and modifiers, so that suppliers can provide the best product to contractors to deal with issues encountered. This information also helps the mix producers understand how different variables can create the most economic and sustainable mixture. Performance testing allows a peek into the future of a pavement’s performance. A key characteristic of a performance test is its ability to correlate with observed field performance. Performance testing also allows for mix design optimization.

QC/QA testing is an intricate and essential process that ensures the quality and durability of roads and pavements. From asphalt core drilling and sample collection to moisture and density measurements of the actual road surfaces, technicians are able to perform extensive tests to refine and improve subsequent asphalt mixes to optimize their properties for better life and travel experience.

Tests for Road Quality
Some of the tests used in these evaluations are dictated by various AASHTO and ASTM standards. Following is a list of these standards, for which Humboldt provides testing equipment.

AASHTO T 283 Tensile Strength Ratio (Moisture Susceptibility)
AASHTO T 324 Hamburg Wheel Tracking Test
AASHTO T 340 Asphalt Pavement Analyzer, APA
AASHTO T 393 Intermediate Semi-Circular Bend (SCB) – I-FIT
AASHTO T 401 Cantabro Mass Loss
AASHTO TP 114 FM 5-599 Shear Bond Strength Testing
ASTM D6931 Indirect Tensile Strength (IDT)
ASTM D8044 Intermediate Semi-Circular Bend (SCB) – LSU
ASTM D8225 IDEAL-CT – CT Index
ASTM D8360 IDEAL-RT – RT Index

Humboldt offers an extensive line of Road Quality Testing equipment listed in this section of our product line. Testing equipment is available for every step of the process, from the monitoring asphalt pavement construction to drilling and retrieval of core specimens, which are used for further testing.

Core Drilling Machines
Core drills are used to extract samples of newly constructed roads, as well as roads that have been in service for a time. These drills use drill bits, which cut a circular sample from a road surface and allows the operator to then remove the material in the form of a rigid core. Asphalt coring is commonly used to assess road quality. Humboldt provides a wide range of core drills from electric- to gas-powered models. There are also models, which are hitch-mountable for fast deployment. Trailer-mounted core drills are also available, which provide a complete core drilling rig, including water tank for cooling the drill bit during drilling. These core drills can handle drill bits as small as 1” for hand-held models up to 16” sizes as well as auger bits.

Asphalt Core Bits
Humboldt offers professional-quality, diamond, drill bits, specifically designed for use in drilling asphalt. They have
a total segment height of .320” (8.128mm), a diamond depth of .250” (6.350mm) and a segment base of .070 (1.778mm). The standard bit length is 13” (330.200mm) and the integral thread adapter is 1.25”– 7 thread.

Nuclear Gauges
Humboldt nuclear density gauges measure density and moisture levels of in-place hot mix asphalt (HMA) using the backscatter method. Gamma rays are emitted from the source and interact with electrons in the material. By calculating the percentage of gamma rays returned to the source, the gauge can quickly and accurately measure the density and moisture in an asphalt road surface. The gauge uses an advanced microprocessor-based technology to provide highly-accurate measurements of density and moisture that are automatically computed for direct readouts of wet density, dry density, moisture content, percent of moisture, percent of compaction (Proctor or Marshall), void ratio and air voids.

TX Pro Overlay Tester
Recent mix design methods are producing materials that are stiffer, leaner and more resistant to rutting, however, these materials are often more susceptible to fatigue and reflection cracking. The TX Pro Overlay Tester was designed to simulate the expansion and contraction movements that occur in the vicinity of joints or cracks and which result in reflection cracking in overlays. It automatically calculates critical fracture energy and crack resistance index according to Tex-248-F.

Hamburg Wheel Tracker
The Hamburg test, or immersion wheel tracking has become an extremely popular test method over the last few years. The Hamburg wheel tracker Humboldt provides is built to withstand the demands of the busiest test labs. It is made of high-quality stainless steel and uses a standard cantilevered arm system of loading the specimens and produces fully sinusoidal motion. Humboldt’s Cox/Cooper machine meets all the requirements of the standards where a number of Hamburg wheel trackers available do not correctly meet the current AASHTO requirements.

Benkelman Beam
The Benkelman beam measures the deflection of a flexible pavement under moving wheel loads. Extremely accurate and easy to use this Benkelman beam supports AASHTO T256. Its direct-reading dial indicator eliminates the need for conversion tables or field calculations, while providing precision accuracy.

Pavement Scanner
Humboldt‘s Pavement Scan Head provides a comprehensive scanning system, which can be used to provide three different integrated methods for evaluating compaction of asphalt surfaces without the use of nuclear sources. At the heart of this system is the scan head, which is used in all three configurations. This scan head utilizes cutting-edge radar technology that measures the dielectric constant of the material and uses these readings to equate to compaction and density readings.

Skid Resistance Tester
Humboldt‘s portable, Skid Resistance Tester Measures friction (skid resistance) on flat, cambered, or gradient road surfaces in accordance to British standards: BS EN 1097-8, BS 812 PT 114. This test apparatus is used to indicate the resistance to skidding of a test surface. It’s portable configuration allows it to be used in the field on actual road surfaces.