Rockster impactor helps with sustainability in Hawaii

Published 9/3, 2021 at 12:12

Alakona Corp from Honolulu has been processing RAP and coral with its new R700S Rockster portable crushing plant.

Alakona Corp, founded in 1982 by Mervyn de Wolff, is an asphalt paving and paving maintenance contracting firm, situated in the Hawaiian capital, Honolulu. Alakona Corp serves Oahu and the neighbouring islands, with a wide list of clients that includes government, commercial enterprises, developers, property managers and individuals. At its beginning, Alakona focused on pavement maintenance, with emphasis on slurry seal, seal coating and minor asphalt repairs. During recent years the company has moved toward its present service/product mix, deriving its income from asphalt repair, asphalt overlay, new asphalt lay, pavement maintenance, as well as slurry seal, seal coat and crack fill.  

Alakona owns several machines including pavers, rollers, loaders, excavators, slurry and seal coat applicators. When looking for a crusher, a focus was placed on compact machinery below 25t. “Wolfgang Kormann (owner and CEO of Rockster) explained in detail how the machine could be beneficial to us and it is true. We are so flexible in terms of processing different aggregates and the material we produce with our crusher is of high value. The screen box is also very beneficial as it allows us to produce different material sizes by just switching some screens. There are some options that others don’t have, and we are very enthusiastic about the hydrostatic drive,” says Alakona Corp’s Arist de Wolff. Thanks to the latter, the performance of the R700S is constantly high, as the hydrostatic pressure always adjusts to the power requirements of the crusher. This leads to a lower diesel consumption per ton of production.


Processing RAP

It was a logical step for Alakona to put emphasis on recycling. “Obviously, natural rock isn’t gonna be there forever, in future we would have to ship it in from the mainland. Sustainability is the key factor. We need a lot of material for subbases, base coarse or backfills. Using RAP instead of natural aggregate saves resources and money. Moreover, RAP contains a bit of bitumen, it is like a glue, holding everything together and giving more compaction,” says Arist de Wolff. “We’re doing a bunch of tests like the CBR, to make sure the final material is suitable for reuse in our construction projects,” he adds. (The Californian Bearing Ratio – CBR - test is a penetration test used to evaluate the subgrade strength of roads and pavements.)

Another material that Alakona processes with the new Rockster crusher is coral. In Hawaii a lot of coral shells are found underneath the soil. So, when Alakona works on street construction sites close to the ocean it usually has to excavate coral. Without a screening system, they run a 75mm minus final product, used mostly for landscaping. “We like the possibility to use the stockpile belt to get another fraction. Coral is quite a hard rock with high density. The crushed material contains less fines than the crushed asphalt. We can use it as base coarse for house or concrete paths,” Arist explains.


Easy transport 

With a screen box and return belt, the Rockster R700S weighs 22.8t and can be easily transported with Alakona’s own flatbed truck without the need of transport permits. This provides great flexibility in terms of the future plan to work as a contractor. It also saves a lot of time and money. “We are able to crush so many kinds of material. Within four days of training this summer, we crushed RAP, coral, concrete and basalt. There are so many possibilities for a lot of different customers like construction companies, privates and of course municipalities. You would think that people on an island would be more aggressive into researching, testing and using recycled material, but they are hesitant in trying new things. It needs to be pushed more and people need to understand that this is the future. There needs to be recycled material especially in construction fields where we could save so much natural resources,” Arist concludes.

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