San Antonio Takes Pothole Patching to the Next Level
BY Mary Foster
Founded as a Spanish mission and colonial outpost more than 300 years ago, San Antonio, Texas, today is home to 2.3 million residents within its metro area. In fact, it is the seventh most populous city in the United States—and just 10 years ago it completed a streak where it was named the fastest growing of the top-10 largest cities in the country.
The city endures long, humid, sweltering summers that are bookended by spring and fall rains. With cool winters, the remnants of an occasional hurricane, and also stretches of hot, dry periods, the city truly experiences all manner of climate extremes throughout the year—all of which can cause havoc with the city’s 4,167 centerline miles of streets and roads.
“The extremely hot weather in our region, along with bouts of rain, create expansion and contraction of asphalt pavement, allowing water to seep into the asphalt and create potholes,” said Frank Orta, operations manager, Street Operations-West, for the City of San Antonio. “Our challenges also include high-plasticity soils with a lot of sand and clay, which hinder our pavement preservation program. With the combination of climate and soils, pothole repair is a year-round effort for us,” he added.
But San Antonio has stepped up its pothole repair game in the past several years, with the addition of four new spray injection pothole patching trucks to its fleet. The SP5 spray injection patchers, manufactured by Bergkamp Inc., are each capable of patching 100 potholes a day, where the city’s conventional trucks typically repair just 30 a day each. They have allowed the city to increase repairs from 35,000 potholes annually in 2016 to more than triple that output in fiscal 2019—while increasing safety for operators and the motoring public.
In 2016, the San Antonio City Council, after listening to community concerns and requests, chose to invest in revamping the city’s street maintenance program—including improvements in the methods used to repair potholes. Pothole patching is a hazardous undertaking for any city, much less a city the size of San Antonio.
With a large number of 5-lane arterial and collector roads, the city wanted to find a solution that could not only improve and increase the patching efforts, but also keep crewmembers safer.
“Even with total lane closures, there is still a safety concern for our crews when they are out working on repairs,” Orta said. “And when you close a full lane, it is also expensive—costing more to close the lane than it does to repair the pothole.”
The city ultimately swapped its aging fleet of pothole repair trucks for all-new equipment in 2017, purchasing 16 new trucks—12 conventional patchers and four Bergkamp SP5 spray injection patchers. While Orta said safety is first and foremost for the city, the fact that the spray injection patchers are capable of repairing 100 potholes a day also factored into the decision to purchase the units.
Ready to Repair
Spray injection is a less invasive patching technique than traditional patching methods, allowing the damaged pavement to be air-blown and repaired in minutes. On the SP5, a front-mounted boom provides a working radius of up to 13 feet in front of the truck. Fully operable from inside the cab for increased safety, the unit requires only one crewmember to operate.
The SP5 features three injectors in a rotating nozzle, which provides the emulsion and aggregate coverage. In a four-step process, the operator blasts compressed air through the unit’s hose to clean out and dry the hole.
The damaged area is then sprayed with asphalt emulsion. The operator selects the proper gradation of aggregate from one of two chambers in the hopper to best match the characteristics of the road, and sprays that over the emulsion. Finally, application of a protective layer of clean stone protects passing vehicles from coming into contact with the asphalt emulsion.
Orta stated that the department liked the fact that “the units are always ready,” in that the operator mixes the emulsion and aggregate onsite as the pothole is repaired. “There is no prior mixing at the shop or material that can go bad,” Orta said.
He shared that they had to experiment some to find the right material and right aggregate for their roads. “For instance, we’ve learned that a Grade 4 washed rock works best for us. Also, we were using a rapid-set oil, but because of our climate, we were constantly having to clean and remove it from the nozzle, so then we went to a CSS1H slow-setting asphalt emulsion, and later to a PHPMS0.”
The spray injection patchers were fully integrated into San Antonio’s fleet by mid-2017. Orta said there was a bit of a learning curve involved in learning how the patchers best operated with San Antonio’s climate. “It’s definitely a skillset. The longer an operator is there in the position, the better the performance you will get from the repair.”
Bergkamp partnered with department members to help overcome the learning curve. The SP5 units the city purchased were among the first-generation units from the company. So, for the 2016 demos, Bergkamp sent engineers, in addition to sales team members, to both demonstrate the unit and answer questions. Then, after San Antonio purchased the four SP5 units, Bergkamp team members came back in 2017 and worked on the learning curve together with the city. Orta said the city has also cross-trained employees so that more crewmembers are familiar with the spray injection patchers.
Engaging and Empowering the Public
Around the same time that San Antonio revamped its pothole patching program, it also provided a big push to empower citizens to call in potholes via the city’s 311 system. With spring being the peak pothole season, the city has created an April awareness campaign for potholes that ties in with the annual Fiesta. “We have a phone bank, hand out literature, conduct interviews with the media and engage the public as much as we can,” Orta said.
The city also has incorporated a full-time pothole investigator into its team, joining four other street maintenance investigators who travel the city’s streets in 10 council districts and proactively call in potholes.
For identification purposes, San Antonio defines a pothole as being 3-foot x 3-foot or smaller.
“We now have a two-business-day guarantee, where from the moment the pothole is identified or reported to our completing the repair, we promise to fix it. So, from Monday through Friday, that’s typically within 48 hours,” Orta said. “It took us about six months to get the program running the way we want it to run. Our goal is to have the machine, the operator and the materials reach perfection,” he added.
As a result of these efforts, Orta said the culture has changed, explaining that eight out of 10 calls in 2015 involved complaints from citizens. Today, only one in 10 calls may involve a complaint, and often that turns out to be a misunderstanding.
“Since we’ve revamped our program, getting the public engaged and proactively searching out potholes, we hear consistently that we are doing a great job. The citizens know we have their backs. When they call in, they trust that we will get out there and repair the potholes quickly. They are seeing the power of a community that invests in its streets,” Orta said.