When to Add More Storage to Your Asphalt Plant

The coming boom in infrastructure rebuilding means it might be time to add more storage capacity to your asphalt plant.

Astec's long-term silos are guaranteed to store conventional asphalt mixes for up to four days and can be utilized as conventional surge bins during busy times of the day.
Astec's long-term silos are guaranteed to store conventional asphalt mixes for up to four days and can be utilized as conventional surge bins during busy times of the day.

In today’s polarized political environment, there’s one area that continues to garner a good level of support from both sides of the aisle: The need to strengthen America’s roads, highways and bridges as part of a comprehensive overhauling of the nation’s infrastructure.

Exactly how and when to get there remains a political hot potato, but many transportation officials and other experts for years have been clamoring for a national effort to get the job done.

Last year the U.S. Department of Transportation, in a status report to Congress, placed the backlog in needed repairs and improvements at $786.4 billion and urged Congress to boost the nation’s annual investment for improving road, highway and bridge conditions by 28.8 percent to $135.7 billion annually.

In addition, data compiled from several sources and released last month by TRIP, a national transportation research organization, claimed that 43 percent of major roads in the U.S. are in poor or mediocre condition, costing nationwide motorists $130 billion a year in repairs, depreciation, fuel consumption and tire wear. While some dispute claims over the seriousness of infrastructure decay, most agree that a major upgrade program is needed across the country sooner rather than later.

“Investments in the surface transportation system will boost the nation’s economy in the short-term by creating jobs and in the long-term will enhance economic competitiveness, stimulate sustained job growth, improve access and mobility, improve traffic safety, reduce travel delays and improve road and bridge conditions,” TRIP noted.

A Wake-Up Call

That’s a good sign for the asphalt industry in general, but it also serves as a wake-up call for today’s asphalt plants to examine best options to increase production and storage in order to take full advantage of the growth opportunities ahead.

Astec, a producer of both warm mix and hot mix plant technology and equipment, reports that its long-term silos are guaranteed to store conventional asphalt mixes for up to four days and can be utilized as conventional surge bins during busy times of the day, while continuing loadout, and allows the plant to begin selling mix right away from full silos in the following days.

“Uninterrupted production runs allow a plant to maximize equipment efficiency and reduce material waste,” according to Astec, which adds that incorporating multiple silos in the plant layout can helps meet customer needs for a number of different mixes. “Silo support structures are designed to meet site-specific design criteria at the location based on the current building codes in the area.”

Long-term hot mix portable, relocatable and stationary storage silo systems feature:

  • Drag conveyors lined with hard alloy castings;
  • Traverse conveyors atop batchers to receive discharge from drag conveyors;
  • Batchers to help eliminate mix segregation;
  • Available bucket elevators;
  • Silo insulation to allow for longer mix storage periods;
  • Cone design that prevents segregation and mix build-up;
  • Specially designed gates at silo bottoms and seals at the silo tops to prevent mix oxidation;
  • Optional blue smoke packages to keep vapor from escaping when filling silos;
  • Supplemental blue smoke packages to control blue smoke emissions during loadout;
  • Foundation designs based on soil conditions at the site;
  • Optional wear resistant lining to achieve virtually unlimited wear life;
  • Other design options to meet plant requirements and/or local conditions. 

Once additional storage capacity is in place, mixtures can be kept in the extra silos for several days and accessible to be loaded into trucks and transported to paving project locations. 

Advanced silos for dry additives also are available for mineral filler, dust or lime in drum mix plants or batch plants. The silos come in several sizes, with options that include leg extensions, baghouses, self-erect and portability packages. Skid mounted liquid additive systems come with controls, pumps, valves and hot oil coils for materials that require heat. 

For plants that want to upgrade storage, but have enough long-term storage and are looking for lower cost alternatives while still boosting capacity and production might consider adding high-efficiency short-term silo systems that can withstand high production requirements.

Short-term silos from Astec range from 100-ton single units to 3,000-ton multiple silo systems with a variety of standard and optional features, among them:

  • Dual clam gates that allow for even and accurate loading;
  • Safety gates as a backup to the clam gates;
  • A reinforced cone with standard electric heat or optional hot oil heating;
  • A support structure with steel beam legs welded to reduce silo set-up time;
  • Industrial-grade insulation to maximize heat retention;
  • Optional blue smoke system to prevent vapor from escaping when asphalt is transferred from the mixer to the storage silo; 
  • Supplemental blue smoke packages to control blue smoke emissions during loadout;
  • Optional wear resistant lining to achieve virtually unlimited wear life;
  • Optional standalone control panel for integration into various control systems.

Another efficient option available to asphalt plants, especially those entering new markets, is to add satellite stand-alone mix storage systems located within transportation radius of a parent plant. “These storage systems produce an opening for expansion into a location that does not yet justify a plant, while the smaller footprint of the silo system can accommodate installation at a small site that can’t support a full plant,” according to Astec.

Teamwork Recommended

Some older asphalt plants may require a re-examination and/or refocusing of the current plant layout to take maximum advantage of an increase in storage capacity and production output, but working closely with engineers and designers at the plant manufacturer should smooth the process. 

Adding to plant storage at an aging facility allows the plant to produce and store asphalt mix in advance, improving efficiency by reducing the need for expensive start and stop operations during the workday to accommodate orders for smaller clients amid those scheduled for larger customers.

At many of the more modern asphalt facilities, new and improved silos often can be strategically and cost-effectively placed within the existing footprint.

Retrofitting an existing asphalt plant with upgraded storage opens the door for greater profitability, but can be somewhat challenging while continuing operations, so close teamwork among plant engineering staff and technical guidance from the equipment maker is recommended to allow for a smooth transition.

Massive Growth Seen

Global asphalt plant market revenue is expected to grow to $2.47 billion by 2027 from $1.93 billion in 2018, representing a compound annual growth rate (CAGR) of 2.8% from the year 2019 to 2027, The Insight Partners research group forecasts in a newly released study. The asphalt plant market was valued at 4,127 units in 2018, according to the report, and is anticipated to reach 4,831 units by 2027, registering a CAGR of 1.8% from 2019 to 2027.

“The companies operating in the asphalt plant market are focusing on offering technologically advanced products that meet the varying demands of the customers,” according to the study, which cites the growing number of highway development projects as propelling exponential growth. “Another factor supporting the growth of the asphalt plant market is urbanization, which is supporting the increasing demand for modern infrastructures such as new roads and highways.”

By acting now to modernize storage and production operations, both new and old asphalt plants will be well positioned to benefit strategically and financially from the growing national need to repair, expand and vastly improve America’s aging road, highway and bridge infrastructure during the decade ahead.