VOL 18 ISSUE #2

According to Corey Clark, director of asphalt and fleet operations with Clark Construction of Texas, Inc., the family-owned and operated road construction’s bread and butter is "mill and lay."

In operation since 1978, Clark Construction specializes in seal coat and hot-mix asphalt projects across Texas. With innovative approaches to the chip seal industry and asphalt paving, the company has excelled in areas of safety, quality, and performance. What has been a contributing factor to its success? A fleet of equipment manufactured and supported by Roadtec.

"We purchased the Roadtec RX-700 Cold Planer in June 2011, and we also have the SP-200 Spray Paver™, SB-2500c Shuttle Buggy, RP-190 Paver, RX-60c Cold Planer, and the RX-600e Cold Planer," said Corey Clark. "On a recent job, we rented the Roadtec RX-600e and liked the milling machine so much that we purchased it for future projects."

The project Clark referred to was the Marble Falls job northwest of Austin, Texas.

Clark Construction
Clark Construction

Blanco County Hwy 281

Marble Falls in centrally located in Texas on Highway 281 in Blanco County. Clark Construction of Texas, Inc. was awarded the road repair project in January 2013. Work began in May on Highway 281 from the Burnet County Line to US 290 West in Johnson City. The 15.051 miles (24.22 km) were set to be repaired using the traditional method of putting down the oil application (tack coat) ahead of putting down mix and sealing with a top coat. Clark Construction was able to have the application method changed to use a membrane underseal and a Roadtec SP-200 Spray Paver. The SP-200 puts down the tack coat just seconds before putting down mix.

This method, according to Clark, is more efficient. "Using the SP-200 is cleaner, faster, and requires a smaller crew." The spray paver used on Hwy 281 was the second machine Clark Construction had purchased from Roadtec. According to Roadtec’s Texas service technician James "JW" Whittington, Clark Construction was instrumental in helping Roadtec develop the first spray paver and purchased the unit in March 2005. Clark Construction traded this older machine for the SP-200 Spray Paver in its current fleet.

Roadtec SP-200 Spray Paver
Roadtec SP-200 Spray Paver

The SP-200 Spray Paver sprays tack and applies hot-mix asphalt seconds later. Combining spraying and laydown produces a high-quality mat with a strong bond between layers. A spray bar just in front of the paver’s auger distributes the liquid through computer-controlled, self-cleaning valves. An onboard microprocessor precisely controls the rate of flow. Valves can also be controlled manually. Valves are arranged in sets of three, providing plenty of spray capacity so you can move fast. To cut down on refill stops, the SP-200 is equipped with a 2,100-gal (7,949 l) tack tank. The spray bars extend as needed with the screed and each nozzle can be manually shut off for partial passes. For paving at any time, a material transfer vehicle (MTV), such as the Roadtec SB-2500c Shuttle Buggy, delivers mix to the spray paver’s gravity-fed hopper, which has a capacity of 11 tons (9 tonnes). The spreading augers deliver the mix to the hydraulically extendable, vibrating screed.

Mill and Lay

The top 1.75 in (4.44 cm) of the highway was milled and replaced with 2 in (5.08 cm) of special specification 3224 dense-graded hot-mix asphalt. The road repair was approximately 15 mi (24.14 km) long and consisted of four lanes (two north and two south). The Texas Department of Transportation (TxDOT) approved SS 3224 for use in May 2011.

Once the milling was finished, the Roadtec SB-2500c Shuttle Buggy fed the Roadtec SP-200 Spray Paver as 2 in (5.08 cm) of hot-mix asphalt was put down. This process of pavement preservation is one of the most cost effective, efficient, and versatile options available on the market. The benefits include reduced noise levels, enhanced skid resistance, and improved ride, drainage, and aesthetics. Overlays can be placed in varying thicknesses, allowing flexibility to design according to the needs of the highway. Future maintenance of the roadway exists through the recycling of materials. Hot-mix asphalt (HMA) consists of well-blended aggregate and asphalt cement—a 100-percent recyclable product.

The road work took Clark Construction through the small town of Round Mountain, population of 182 (according to the 2011 census). A few weather-related delays hampered progress, but with the Roadtec equipment, Clark Construction kept pace and completed the project on time.

"The project took about two months," said Clark. "We experienced some rain delays and were pushed on the schedule, but with the Roadtec equipment, we finished the project on time near the end of July."

Clark continued, "We put down approximately 60,000 tons (54 tonnes) of asphalt on the project. The Roadtec machinery held up well and we experienced fast production. The support we receive from Roadtec is essential to our success, and having a Roadtec fleet of equipment provides the right tools for what we love to do best ... mill and lay."

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