The RA-300 spray injection patcher, with its one-person, from-the-cab operation makes safely and effectively repairing potholes a year-round activity. The RA-300 features its in-cab controls, full-function spray nozzle with joystick control and front-mounted patching boom and rear-mounted arrowboard. Its hydraulic “Patch-on-the-Go” feature allows for patching on the move with no auxiliary power.
Spray patching with the RA-300 is a four-step process. First, the pothole or crack is cleaned using a high-volume blower that provides a blast of air to remove loose rock, dust and debris. Second, a tack coat of hot asphalt emulsion is applied to the area to ensure proper adhesion to existing pavement. Next, aggregate and hot asphalt emulsion are combined and shot into the pothole or crack using forced air. Finally, a topcoat of aggregate is applied and traffic can flow immediately. This “bottom-to-top” method of patching results in a quick, compacted repair that lasts significantly longer than other patching methods.
According to a 1993 Strategic Highway Research Program (SHRP) study, spray patching has a lower failure rate, is more cost-effective and requires less installation time than other patching procedures.
The RA-300’s in-cab control of all patching functions allows for patching in extreme weather conditions, but transforms what is normally a multiple-person job into a safe, single-person task. With a pistol-grip joystick, the operator can position the asphalt spraying boom to the desired position, clean the area intended for repair, fill the crack or pothole and finish — without leaving the enclosed cab. This reduces job-safety concerns and cuts down on the expense of multiple operators required by other patching systems. Additionally, no compaction is required with asphalt spray patching.
A key feature of the RA-300 patcher is its full-function spray nozzle. Used in every step of the patching process, the nozzle has no spray ring to clean, no gaskets to replace and features heated lines that extend all the way to the nozzle end. This results in dependable, maintenance-free operation, patch after patch. Additionally, the RA-300’s three-stage telescopic swing boom provides the largest working area of any equipment in its class.
The RA-300 includes many wear-prevention features. An automatic take-up reel controls the length of the emulsion hose to accommodate various boom positions during operation. To further minimize maintenance, the RA-300 uses an aggregate feed hose from the hopper slide gate to the front bumper. This allows low-pressure air to move material from the hopper to the patch, instead of higher-maintenance moving parts. Also, the aggregate delivery tube is constructed of PVC piping, which lasts longer and requires less maintenance than other systems.
To maximize working time, the RA-300 is built with an aggregate hopper capable of holding up to 5 cu. yds. (3.8 cu m) of material —enough for a full day of patching. Asphalt is replenished through a 12-in. (30 cm) load hatch located on top of the 400-gallon (1,500 L) emulsion tank. For extended operation, the Hopper Heat system uses heat from the engine to prevent the aggregate from freezing and allows for year-round patching. Also, the Hopper Vibrator prevents “bridging” of aggregate, while the Water Flush Kit moistens aggregate for better adhesion and dust control.
The RA-300 includes an arrowboard mounted on the back of the chassis that safely directs traffic around the work zone. Combined with the fact that the operator is not required to leave the cab during any step of the process, job-site risk is greatly reduced.