The Marathon MM250ADT is the auger-drive version of Marathon’s 250-gallon mastic trailer, and it exists to solve a specific problem: the heaviest, densest mastic materials do not pour well. Gravity discharge works fine for standard grades, but as material gets thicker and more heavily filled with aggregate and fiber, flow rate becomes inconsistent and placement becomes difficult to control. The Helix auger system replaces gravity with a driven, metered discharge.

Critically, the auger assembly is itself oil jacketed. Marathon’s specification calls for a dedicated heat transfer oil feed port for the auger, positioned at least 9.5 inches above the oil vat floor, with corrugated stainless braided hose carrying heated oil to the assembly. Rubber, hydraulic, and PTFE-lined hoses are explicitly deemed unacceptable at those temperatures. The auger assembly is finished in a high-temperature coating. The practical effect is that material stays at working temperature all the way out of the machine, which is exactly where dense mastic normally chills and seizes.

The auger runs on its own hydraulic circuit. Where the gravity model uses a single 6 GPM pump, the MM250ADT uses an engine-driven double-stacked pump rated 16CC/8CC with dual 1.5-inch suction strainers, so agitation and auger discharge can be driven simultaneously without one starving the other. Auger forward and reverse plus heated oil flow are controlled from a hydraulic manifold with lever handles mounted on the rear wall, right where the operator is working, with a dedicated analog pressure gauge for the auger circuit.

Controlled dispensing is what unlocks wide-area repair. With Marathon’s optional adjustable drag box, up to 4 feet wide, towed behind the trailer, a crew can lay mastic across a full wheel rut in one uniform pass rather than pouring and hand-working it. This is the technique behind Marathon’s documented rut-leveling work on rural roads, where mastic replaced full-depth milling and paving and eliminated the milling machines, spoil removal, and crew size that conventional resurfacing requires.

Everything upstream of the discharge matches the proven MM platform. The tank is a double-boiler oil-jacketed design with a 250-gallon (946 L) working volume, built from no less than 1/4-inch steel, with a 10-gauge firing chamber lined in 1.5 inches of ceramic insulation on all four surfaces. A minimum 45-gallon (170 L) reservoir of Shell S2X ISO 68 heat transfer oil circulates through a jacket covering the front, rear, and both sides of the vat. A single 12-volt 340,000 BTU self-priming diesel burner supplies the heat, with an external green LED beacon showing burner status, and the machine is specified to reach pouring temperature from ambient in under two hours.

Agitation uses the same full-sweep horizontal design with angled paddles, driven through a HECO Gear model 16 gearbox at 5.2:1 producing 2,500 ft-lbs, running forward and reverse. Dual digital thermostat controllers hold material and oil to their setpoints within one degree Fahrenheit via continuously monitored thermocouples, shutting the burner down with an error code on any thermocouple failure. Two 1,500W 120-volt overnight heaters mounted in protective enclosures on opposite sides of the rear wall keep material warm between shifts.

The engine is a Rehlko three-cylinder, direct-injected, water-cooled 23 hp Tier 4 Final diesel with electric start and auto-shutdown protection for alternator, oil pressure, coolant temperature, air filtration, and low voltage, with faults and hour meter displayed on an illuminated control box. A minimum 30-gallon (113.5 L) lockable diesel tank feeds engine and burner through separate spin-on filters.

The trailer is rated for highway towing fully loaded, on a 6-inch by 8.2-pound gusseted steel channel frame with a tandem slipper spring axle system at 14,000 lb (6,350 kg) GAWR, electric brakes on all four wheels with breakaway, and ST235/85R16 Load Range E radials on aluminum rims. Auger discharge clearance is a minimum 24 inches to grade, leaving room to fill a heated chute or the MD12 walk-behind dispenser.

Safety carries the same standards as the rest of the line: a top loading door interlock that stops the agitator when opened, a 60-inch maximum loading height, a vented oil expansion tank, a 10 lb fire extinguisher, heat-resistant decals, and conspicuity tape along the frame. The fender-mounted heated tool box includes an 8 by 4 inch smoother, a 12-inch flat squeegee, and an 18-inch U-squeegee.

For contractors specializing in rut and wide-area mastic repair, the MM250ADT is the machine that makes those jobs practical. Roadly supplies and supports Marathon auger-drive mastic trailers across Canada.