Pavements

---

ROSAN Makes Manual Pavement Testing Obsolete

In 1997, the FHWA's Pavement Surface Analysis (PSA) Laboratory at the Turner-Fairbank Highway Research Center (TFHRC) will debute their series of Road Surface Analyser (ROSAN) devices. The ROSAN series includes ROSANbp, ROSANv, ROSANvm, and ROSANvm(P).

Each device electronically records the surface macrotexture depth of any transportation surface, some at highway speeds up to 120 k/ph. ROSAN results are fast, accurate, and easy to obtain, thus promoting safety while eliminating costly traffic control and the operators influence on the test procedure and site selection. Besides macrotexture, ROSAN can measure faulting, grooving/tining, rutting, slope, and road profile. ROSAN can be used on grooved/tined pavement, roads, bridge decks, airport runways, and sidewalks.

Using ROSAN, manual pavement testing like this is now obsolete.

The ROSAN devices incorporate the following hardware in various combinations: laser sensors, accelerometers, distance pulsers, bumper-mounting hardware, a vehicle-mounted beam, and a motorized trolley. The hardware are controlled by a TFHRC-written, Windows-based program, and is very user friendly. Depending on the selected device, data collection can be initiated manually or optically triggered and can be collected at 1 mm intervals for distances of 1 to 800 m.

ROSAN calculates the Estimated Texture Depth (ETD) and is useful as a tool in characterizing pavement surface texture. This value is comparable to the Mean Texture Depth arrived at by ASTM E 965, Standard Test Method for Measuring Surface Macrotexture Depth Using a Volumetric Technique, also referred to as the Sand Patch Test. The ETD may be used along with other physical tests such as skid resistance (i.e. skid numbers) to obtain the International Friction Index (IFI.)

Currently ROSANbp, ROSANv, and the accompaning software are available for loan as they undergo the patent application process.

-- Dennis Sixbe (202) 493-3078

---

Truck-Pavement Interaction Team
Helps Complete International Study

The Organization for Economic Cooperation and Development (OECD) DIVINE (Dynamic Interaction Vehicle Infrastructure Experiment) program, is an ambitious international cooperative research project focusing on how roads and bridge structures are affected by heavy vehicle vertical dynamics. Bill Kenis, who is the Vice-Chairman of OECD scientific expert group IR6, led an FHWA Truck Pavement Interaction team which contributed to the project. Other major participants to the DIVINE project include Australia, Canada, Finland, France, Germany, Great Britain, Japan, the Netherlands, New Zealand, Sweden, and Switzerland.

Extensive technical work in the area of pavement variability, response, and vertical dynamics have been completed by FHWA's team. There are six elements of this study. Element Two, involving testing of flexible pavements, was completed at TFHRC. The Truck-Pavement Interaction team has also completed and is validating an extensive computer simulation model to calculate wheel forces of heavy vehicles for Element Four of the study.

The Truck-Pavement Interaction team will participate in the DIVINE Concluding Conference, which will be held in Ottawa, Canada, June 1997. The National Research Council of Canada will host the concluding conference. To receive more information about the conference contact:Conference Secretarial Pierre Lamoureux, Conference Manager, DIVINE Concluding Conference National Research Council Canada Ottawa, Ontario, Canada K1A OR6.

-- Bill Kenis (202) 493-3194

---

Mobile Pavement Retroreflectometer Tested

FHWA has sponsored the development of a mobile pavement marking retroreflectometer that measures retroreflectivity in daylight at highway speeds. This equipment is a powerful tool for collecting retroreflectivity information, providing more than 300 readings per kilometer when measuring solid lines.

A series of static and dynamic test runs with three retroreflectometer units were carried out near Minneapolis in September. The objective was to assess the relationship between retroreflective values measured under the European Committee of Normalization (CEN) and the mobile retroreflectometer geometries, the repeatability and reproducibility of the measurements, and the influence of the roadway segment length on the precision of the determinations.

The dynamic tests consisted of repeated measurements of four pavement marking lines in two different highway segments performed with the three retroreflectometer units in sequence. The results show that good levels of repeatability can be achieved with the mobile retroreflectometer when operational procedures are set and strictly applied. Precision of the measurements increased with segment length. Station lengths of 0.8 km for solid lines and 1.6 km for skip lines measurement were found to maintain measurement tolerances within reasonable limits.

A report on these tests has been prepared. The publication number is FHWA-SA-97-016. Copies of the report are available upon request from the Office of Technology Applications.

-- Jose M. Pardillo (202) 366-2094

---

ARMM Promises a Helping Hand

Pavement crack sealing is a widespread, dangerous, costly, and labor intensive operation. Labor turnover and training are increasing problems related to crack sealing crews, and as traffic volumes increase, crack sealing operations become increasingly disruptive to the general public. Automating crack sealing can reduce labor and road user costs, improve work quality and decrease worker exposure to roadway hazards.

Automated pavement crack sealing technology has been developed through a series of government and industry funded projects, culminating in a very promising prototype being tested at the University of Texas at Austin. The Automated Road Maintenance Machine (ARMM) follows like a trailer attached to a maintenance vehicle. The ARMM will scan the pavement area beneath the trailer and map any cracks on a computer in the maintenance vehicle. The operator, seated safely in the vehicle, can then use keyboard commands to initiate the automated crack sealing process.

The ARMM can lend a helping hand by saving time and money on crack sealing operations.

Test results indicate that the ARMM can be twice as productive as the conventional, labor-intensive crack sealing method. Adoption of this new technology could produce significant savings in the $200 million spent annually on crack sealing operations nationwide.

Field trials of the equipment began in the fall of 96. The latest work is being funded through the Priority Technology Program (PTP) utilizing a public-private partnership between Crafco, the Texas DOT, and FHWA.

-- Michael M. Moravec (202) 366-6626