Frequently Asked Questions (FAQ)

1. What does the Rubble Master Compact Recycler Crush?

The Rubble Master Compact Recycler product line is designed from the ground up as aggregate based recycling equipment used to recycle Concrete, Asphalt, Brick, Block, Precast concrete and natural stone.

2. Can I crush wood in the Rubble Master?

No, The Rubble Master Compact Recycler utilizes a Horizontal Shaft Impact (HSI) Crusher. This machine is used to exclusively crush aggregate base construction materials.

3. How long does it take to set up the Rubble Master for production?

The Rubble Master can take as little as 10 minutes to set up the crusher from the time you walk it off of your lowboy trailer. If you choose to utilize the closed circuit options available for the RM80 and RM100 models setup can take as much as an hour prior to crushing.

4. What is the difference between a diesel electric and diesel hydraulic configuration?

Diesel electric configuration refers to how the majority of a compact recycler’s components are powered. A Rubble Master Compact Recycler’s primary components are primarily electrically powered. These include the vibratory feeder; the Conveyor drives and control system are power by the generator powered by the diesel power pack.

Nearly all other manufactures utilize a hydraulically powered vibratory feeder and conveyors, while many manufacturers even power the crusher drive hydraulically. A typical Diesel hydraulic configuration can have as much as 400% the fuel consumption of an RM series crusher while producing nearly the same tonnage of finished product. Rubble Master’s diesel electric design allows the operator to remotely track the RM80 and RM100 Compact Recyclers while it is crushing, increasing productivity.

5. How much does the Rubble Master Weigh?

The Rubble Master Compact Recycling crushers weigh as little as 13 tons and as much as 31 tons. All models of the RM series crushers are eight feet wide or less and are road legal for most lowboy tractor-trailer combinations. This combination makes it the most compact of all of the mobile recycling crushers while its production capabilities make it the most efficient in the market.

6. Why is it important to be able to track and crush at the same time?

While crushing on-site it is often important to maximize the job site layout. This can easily be done with the Rubble Master Compact Recycler as you are crushing the operator moves the crusher in a matter that the operator creates wind rows of finished crushed product. This is accomplished through the operator’s use of the radio remote control from the cab of the excavator, minimizing crusher down time.

7. How does the Rubble Master create a gradable aggregate in one pass?

When recycling concrete or asphalt or while crushing natural aggregate the design of the Rubble Master impact crusher utilizes reduction ratios commonly associated with impact crushers. Since common gradations of a gradable base aggregate range in size from ¾” to 1 ½” these material specifications can be met as long as the feed material is properly sized. Horizontal Impact crusher reduction ratios of 20:1 are common and therefore when a 1″ base material size is required the feed size of about 20″ will produce this gradable aggregate. Feeding material larger than this will result in a larger finished material size as well as a reduction in productivity. With the closed circuit design of the RM80 / RM100 Compact Recyclers, the majority of this material meets the specification in one pass while any over sized material is recirculated back through the crusher sizing the material with in the proper size range. The Rubble Master crusher’s unique crushing chamber design maximizes the reduction ratios common with horizontal impact crushers while minimizing the excessive generation of fines.

8. Why does an impact crusher create a more consistent material gradation than a jaw crusher?

The nature of a horizontal shaft impact crusher produces finished product with a reduction ratio of about 20:1 while jaw crusher will utilize much lower reduction ratios. The design of a compression (jaw) style crusher is principally used as a primary crusher due to its much lower reduction ratios. An impact crusher will generate more fines than a jaw crusher upon its initial pass while the secondary crushing required to produce a gradable aggregate initially crushed in a primary jaw crusher will generate a higher percentage of fines.

In addition to the gradation of the material, particle shape is also very crucial to meeting gradable material specifications. The shattering of the material in a horizontal shaft impact crusher creates a more consistent cubical material shape. While a compression crusher such as a primary jaw or even a secondary cone crusher will produce a lot higher percentage of flat or elongated particles. Nearly all material specifications require the rigid spec base rock must be cubical in shape in order to lock into place to meet the high percentage of compaction.

9. How long does a set of hammers last?

This is the second most common question asked of the RM series of crusher. When estimating wear life many variables need to be considered.

• Material Feed Size
• Moisture Content
• Hardness of the Material
• Wear Part Selection

When feeding material into the crushing chamber the greater percentage of fines the higher the wear factor. The wetter the material the more abrasive it becomes. One of the most abrasive materials is actually asphalt because of the hardness of the sand and the lubricity of the asphalt makes for a very abrasive combination. We can estimate wear life and calculate an expected wear cost for you but it will rely on the materials you are crushing, in the environment you are crushing at the production rates you will be able to attain.

10. How well does the Rubble Master handle wire and rebar imbedded in the concrete?

When prepping the material during demolition the rebar needs to be reasonably trimmed so that it will not be wound around the rotor inside the crusher housing. This being said the RM Series Compact Recyclers utilize a permanent earth magnet Magnetic separator that will typically remove over 90 — 95% of the steel in reinforced concrete. The size in which the material is prepped to, the crushed material size and the production capacities will affect the efficiency of the magnetic separator. Even though the scrap price for rebar is lower than most, this revenue steam can be significant over the course of a demolition project.

11. How does on-site recycling make me as a contractor more profitable?

There are several ways in which On-Site Recycling will make you more profitable in your market but more importantly much more competitive than a conventional contractor. Some of the cost savings associated with on-site recycling include transportation costs, tipping fees for the disposal of C&D materials, the transport and the purchase of aggregate materials required for the final site work.

By Recycling concrete, asphalt, brick and block construction materials on-site, you are turning this construction waste into a viable product to be sold right back to the project. Depending on the requirements in your local area disposal fees can range anywhere from a couple dollars per ton to more than $15 per ton. The transportation cost of hauling away the recyclable material is totally dependent upon your hourly rate, but is most often reliant on the cycle times to and from your dump site. A rural contractor may get as may as 8 — 10 loads per truck per day while a contractor in a major metro area could be strapped with as few as 4 cycles per day. This example alone just doubled the transportation cost of a project. The cost of aggregate materials needed to finalize the site work on a project range in price from as little a $5 per ton to more than $20 per ton depending on the region in which you are located. When the concrete on a job site can be utilized as this aggregate once it is recycled on-site, the cost savings can be astronomical. These costs can have a significant impact on how the job is bid, while on-site recycling will change your profit and competitive position in the market. With a Rubble Master Compact Recycler crushing on-site can be feasible with as little as 1000 tons. Where as with conventional crushing contractors the foot print required to crush on-site and the mobilization and set up time typically require several thousand tons to make on-site recycling feasible.