Road roller (compaction roller)

01

Choose the roller type for the material and specification

Texas DOT's 2024 specification Item 210 (Rolling) lists roller requirements by type: static steel-wheel rollers for embankment, subgrade, base and asphalt concrete weighing at least 10 tons with at least 325 lb per inch of wheel width at 2–3 mph; tamping rollers for embankment and subgrade with feet exerting 125–550 psi and projecting at least 3 in.; heavy tamping rollers at 550 psi or more; vibratory rollers for embankment, subgrade, base and asphalt as Type A (static weight under 6 tons), Type B (at least 6 tons) or Type C as shown on the plans; and light, medium and heavy pneumatic rollers by load and tyre pressure, for example medium pneumatic rollers of 12–25 tons at 80 psi or more. [1]

The specification allows vibratory rollers to be used in static mode where static steel-wheel rollers are required, requires pneumatic tyre rollers to have rear tyres covering the gaps between the front tyres and smooth-tread tyres for asphalt, and asks for the operating load and tyre pressure to be kept within the manufacturer's charts. [1]

Editorial note: highway agencies set their own roller rules; obtain the specification for the project and check each offered roller against its type, weight and contact-pressure requirements.

Give the supplier the materials and layer thicknesses (soil type, granular base, asphalt), the contract specification, required density and test method, working width and area per day, gradients, transport limits, emission standard, water spray and edge-cutting needs, and any intelligent compaction or measurement system required.

02

Set vibration, centrifugal force and working speed

For vibratory rollers, Item 210 requires separate frequency and amplitude controls for each vibrating drum, manual start and stop of vibration and a drum cleaning mechanism; settings must follow the manufacturer's specifications to compact without displacing or shoving material, and rollers must travel at speeds that give at least 10 blows per foot unless the plans say otherwise. For asphalt, the roller must also reverse the eccentric, stop vibrating before the roller stops and keep the drum wetted. [1]

ACE lists its AT212 to AT220 mechanical single-drum vibratory rollers at 12,000–20,000 kg operating weight, static linear load of 276–460 N/cm, frequency of 30 Hz, amplitude of 1.6/0.8 mm to 2.0/1.0 mm (high/low), centrifugal force of 270/140 kN to 360/220 kN, 2,100 mm vibrating width, 35% gradeability and first-gear speeds of 1.8–2 km/h. It describes them as suited to non-cohesive materials such as sand, gravel, crushed stone and rock fill. [2]

Editorial calculation: at 30 Hz the drum delivers 1,800 blows a minute, so the Texas minimum of 10 blows per foot limits speed to 1,800 / 10 = 180 ft/min, about 2.0 mph or 3.3 km/h; the AT-series first and second gears (1.8–4 km/h) bracket that limit. [1] [2]

03

Read a second maker's single-drum specification against the same rules

Caterpillar's CS56B vibratory soil compactor, a discontinued model whose specification is still published by Cat dealer Quinn Company, shows the figures a single-drum soil roller sheet gives and how they differ from ACE's AT series. The CS56B has an 84 in compaction width on a 60.4 in diameter drum, a 25,346 lb operating weight with cab, a static linear load of 164.1 lb/in with ROPS/FOPS (166.5 lb/in with cab) and a Cat C4.4 engine of 157 hp gross. [4]

Editorial calculation: 164.1 lb/in is about 287 N/cm, close to the 276 N/cm low end of the ACE AT range, and the 67,600 lb and 31,670 lb forces are about 301 kN and 141 kN, against ACE's 270/140 kN to 360/220 kN. At the standard 30.5 Hz, TxDOT's minimum of 10 blows per foot limits working speed to 183 ft/min, about 2.1 mph; at the 23.3 Hz bottom of the variable range the limit falls to about 140 ft/min (1.6 mph). The 7 mph maximum travel speed is therefore a transport figure, not a compaction speed. [4] [2] [1]

Editorial calculation: 25,346 lb is about 12.7 US tons, above the 6-ton static weight that divides TxDOT vibratory Type A from Type B, while its 164.1 lb/in static linear load is about half of the 325 lb per inch Item 210 lists for static steel-wheel rollers. Check each offered roller against the exact roller type the plans call for. [4] [1]

04

Roller ranges on the listed makers' own sites

The suppliers reviewed list mini, tandem, single-drum and pneumatic rollers; ask each for static weight and linear load, frequency and amplitude settings, centrifugal force, drum width, speeds, gradeability, engine and emission stage, and water system.

05

Specify intelligent compaction where the contract calls for it

FHWA's July 2011 Focus article (FHWA-HRT-11-015) describes intelligent compaction (IC) for hot-mix asphalt as using a self-propelled double-drum vibratory roller fitted with accelerometers mounted on the roller, an onboard computer that evaluates the pavement's response to the compaction effort, pavement surface temperature sensors, color-coded display units and GPS that monitors the roller's operation and location. The accelerometer-based measurement is called intelligent compaction measurement values (IC-MV), and a correlation with pavement cores from a test section lets the crew evaluate compaction in real time. [3]

FHWA reports that a 3-year pooled fund study launched in 2007 (TPF-5(128)) ran 16 IC demonstrations in 13 States, and that its Veda software plots IC-MV against roller pass counts as a compaction curve to set target IC-MV and optimal roller passes, with data from multiple roller manufacturers. On the display it describes, red marks areas with one pass, yellow two, blue three and green four overlapped passes. Ask the supplier which IC measurement the roller reports and whether its data export is accepted by the project's software. [3]

06

Drum, exciter, tyres and spray: what each roller part does

The water or release-agent system and the drum cleaners come from Item 210's rules for rolling asphalt; drum width and gear speeds come from ACE's AT-series sheet.

07

Quote fields checked against the AT sheet and Item 210

Travel speed is the field to set from the job rather than copy from a brochure, because Item 210's blows-per-foot rule ties it to drum frequency; engine, fuel and water-tank values have to come from the supplier.

08

Send the material, specification and site data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Materials: [soil; base; asphalt; layer thickness]
Specification: [agency; roller type; weight; pressure]
Vibration: [frequency; amplitude; force]
Speed: [impact spacing; gears]
Site: [area per day; gradients; transport]
Systems: [water spray; measurement]
Engine: [power; emission stage]

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