THE AGGREGATE:

We recommend a 2-3” lift (50mm – 75mm) of 1/2” to 3/4” road crush with 25-30% fines to bind the aggregate together with the application of the oil. The application rate will vary from 4 to 6 liters per square meter, depending on the amount of aggregate and the type and percentage of the fines in the material.

APPLYING S.B.-90 LIQUID ASPHALT:

The two most efficient methods of mixing S.B.-90 Liquid Asphalt are with motor graders or a pugmill.

Motor graders are readily available, either owned or contracted by the customer. This practice is by far the most common method of mixing the product. The process can be expedited with the addition of road construction mixers or tillers. And of course motor graders are required to lay the finished product regardless the mixing method.

For projects requiring large volumes of oil to be mixed for immediate placement or for stockpiling, we highly recommend the use of a pug mill. This achieves a more consistent blend of oil to aggregate and is not subject to some restrictions that may halt a “mix in place” operation such as wet gravel at the job site due to rain. Pug mill mixing can continue after a rain while “mix in place” projects would require drying time for the aggregate which could result in days of lost time.

MOTOR GRADER MIXING

Motor grader mixing is the most common method of applying road oil, but it is the most time consuming and requires that conditions be extremely favourable at the time the job is performed.

Weather conditions are very critical as the aggregate must be dry before applying the oil (this is a non-emulsified oil product and does not mix with water). SANDS must be allowed to exercise the option to delay application if their application consultant deems aggregate and weather conditions to be unfavourable.

A typical application requires that the windrow be shaped to be even and consistent to attain the best possible mix. Good gravel checking will help when the material is placed. The windrow is then flattened to an 8 to 10 foot width and oil is applied with SANDS’ distributor truck.

The graders proceed to mix the oil into the aggregate. SANDS’ consultant will instruct the operators as to the fastest and most efficient methods for mixing. After a few rolls, the windrow is again flattened for another application of oil. Typically, three to four passes will be required with the oil distributor. The material is rolled continually until the optimum mix is achieved.

When the mixing process is complete, the SANDS consultant will instruct the grader operators in placing the material to an even depth across the roadway. We recommend that the width of the road be staked prior to application in order to assist the operators in achieving a consistent width when spreading the material.

After the material is spread, SANDS recommends compaction with a rubber wheeled packer. A steel drum will help to smooth the surface, but can only be used after initial compaction by the rubber wheeled unit or by a day of regular vehicular traffic.
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Motor Grader Mixing

PUG MILL MIXING

Pug mill mixing provides a superior method of blending oil with aggregate and SANDS can provide a mobile pug mill to your site for larger projects.

Once mixed, the material can be placed and packed as conditions allow (i.e., weather, manpower and equipment availability), yielding a superior end result compared to in-place blade mixing, and greatly reducing grader time and costs.

Optimum mix design of S.B.-90 Liquid Asphalt to aggregate varies from 4.5% to 5.3% depending on the specs of the aggregate.

SANDS will deliver a minimum of 81 tonnes of oil to the mixing site daily. Mixing capacity of the mill can be as high as 120 tonnes daily if conditions are optimal. Mixing will proceed daily non-stop (weather pending) until your project is completed.

Mixed aggregate can then be moved for placement in as little as two days after commencement of pug mill mixing. We suggest this mixing “lead time” in order for mixing to stay ahead of rapid material placement.
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Pug Mill Mixing

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