• Senn Blacktop: Recycle & Reuse

    Senn Blacktop, a 3rd generation, locally owned paving contractor, serving most of west-central Wisconsin and beyond, somehow manages to do it all at the company site in Chippewa Falls, WI. The company crushes and screens its own aggregate and millings, in addition to recycled asphalt paving (RAP) hauled into their site. Their 2017 Lippmann-Milwaukee also crushes the concrete recycle used in their road bases. Senn meticulously grinds and screens recycled asphalt shingles (RAS) for use in its asphalt mixes, a job many asphalt producers sub-contract to other firms.

    Asphalt mixes are developed and tested in the lab on site. Their HMA is produced in their completely computerized, 2011 asphalt drum plant. Their six prep and paving crews lay new asphalt for residential, commercial, and road projects using their own fleet of trucks, heavy equipment, pavers and rollers, (plus some hired trucks.) By using this “hands on” approach each step of the way, Senn Blacktop is able to maintain tight quality control over all the ingredients and processes in the asphalt mixes they produce.

    Darrin Senn, president of the company since 2000 has made several new equipment choices to increase Senn Blacktop’s efficiency and profitability. In his first major purchase in 2011, he replaced their Stansteel asphalt plant that had given Senn over 40 years of service, with a new, energy-efficient, completely computer-controlled drum plant. Custom Welding and Metal Fabricating, Inc. of Waite Park, MN, built the new plant, which has two 200-ton silos. “They custom-built the drum for us and provided and set up the plant,” explained Senn.

    The plant was designed to incorporate recycle in their asphalt mixes efficiently. “It is set up to convey the recycle into the drum at the collar to prevent burning off of the oil in the recycled shingles and recycled asphalt paving.” The system includes a baghouse for air quality protection, and is heated by natural gas. The new plant has given the company more precision in its asphalt production.

    “This plant produces thousands of tons of asphalt, to specs, per day from spring through fall,” he added. Much of their asphalt contains recycle, to the great benefit of area landfills. “However, the local landfill still accepts asphalt shingles. We are working with them to change that. We charge no tipping fee here for shingle disposal.”

    Senn’s asphalt mixes frequently contain polymer-modified asphalt. “We also use an additive that helps in getting the stiffer, oxidized asphalt from the shingles moving throughout the mix structure.” Senn holds to a “chocolate milk theory” on recycle. “If you put 6 percent (by weight) of chocolate chips in a glass of white milk, you do not have chocolate milk,” he explained. “It isn’t until you heat and thoroughly mix the ingredients that you effectively have true 6 percent chocolate milk.

    “This is the industry challenge with recycled asphalt products of any kind. Getting the reclaimed oils to travel throughout the mix and coat the particles is key.”

    The next major purchase by Senn Blacktop in 2016 was a Rotochopper B-66 with the optional asphalt shingle grinding package to replace their previous Peterson grinder. The new Rotochopper produces a more uniform product. Senn’s most recent purchase was a new prima crusher, a 2017 Lippmann-Milwaukee 4248 LP impact crusher. Senn was attracted by the Lippmann reputation for a long, trouble-free working life and this crusher’s large feed opening, among other factors. When crushing the hard river stones he uses for aggregate, Senn adds a Lippmann 2142 Jaw to his crushing line.

    Senn owns a veritable fleet of Blaw-Knox and Ingersoll Rand pavers, in addition to Volvo 180, 220, and 330 loaders for their fuel efficiency, Sakai Rollers, Sterling and Freightliner dump trucks, CAT excavators, and several track skid steers. Multiple paving crews, each headed by an experienced crew leader, aim to please, from pre-cleaning to leaving a clean job site behind. The company is committed to completing each job to the customer’s satisfaction. “We treat every project as if it is our own.” Their A+ Better Business Bureau rating is proof of their success.

    In the company’s lab, all the hot mix and warm mix designs are developed and tested by quality control manager Jeff Novak. Because the amount of asphalt cement in recycled shingles and RAP can vary significantly, Novak regularly tests samples of RAS and blacktop to determine their asphalt content.

    Further testing of each mix, using a Troxler gyratory, A Geotest compactor, and a set of vibrating screens of graduated sizes, among other devices, ensures that each HMA and WMA mix falls within the parameters for the job.

    Darrin Senn earned his position every step of the way from late childhood on, and in the process, he learned to understand the company and its operations, and also to envision its future possibilities from the ground up. Starting with sweeping up, mowing grass, steam cleaning and painting, Darrin moved on to the crushing crew. During college he spent his summers working on the paving crew. After graduation in ‘96, he began buying company stock, and spent several more years in preparation, working as Operations Manager.

    Finally he was handed his first big project to manage, the Stanley Prison in Stanley, WI. While on that first project, Darrin’s management capabilities quickly came up-to-speed, and his judgment matured. With this “hands- on” education — wisely required by his Father and Uncle — Darrin was fully prepared to assume the company presidency in 2000. Not surprisingly, the company has grown and prospered under his well-honed leadership.

    Senn Blacktop began producing RAP in the 1990’s and worked with the DNR on methods to use RAS successfully in the early 2,000s. The company’s use of recycled materials has become a selling point with their environmentally conscious customers, as well as a ‘green environment’ cause for Darrin because it “affects landfill space and the use of oil, which is a non-renewable resource; lowers the cost of roofing and paving; and turns a used product into a valuable resource,” while making a stronger blacktop.

    A portion of Senn’s asphalt production is also sold to other contractors, counties, and municipalities; both as warm mix and hot mix asphalt. “Most of our warm mix is used on rural town roads,” Darrin explained. “We started experimenting with warm mix about 3 years ago.”

    This year, Senn Asphalt’s computerized plant is on course to produce 35,000 tons of warm mix asphalt, and a total of nearly 200,000 tons of hot mix and warm mix combined.

     

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