The leading voice for the crushed stone, ready mixed concrete, sand and gravel, and cement industries' community.
PELA is a 10-month hybrid program with online and in-person educational sessions and networking opportunities.
Careers in the Aggregates, Concrete & Cement Industries
The Pennsylvania Aggregates and Concrete Association (PACA) is the industry’s unified voice, representing more than 200 member companies across the state.
Creating a unified and strong voice for our industry.
PACA monitors and analyzes local, state and federal regulations and advocates for a balanced approach by the regulators.
PACA builds a bridge between our members and our partners at PennDOT, and the Pennsylvania Turnpike Commission along with Pennsylvania’s construction industry to further the use of our materials to the benefit of the commonwealth.
One of the most effective tools in government relations for an industry is a robust advocacy/grassroots strategy.
In the last legislative session, we contributed over $275,000 to our political champions.
November 2025 at Hotel Hershey in Hershey, PA (PACA members only event).
PACA offers comprehensive concrete certification programs for ACI, NRMCA, and PennDOT in the central Pennsylvania area.
Membership has its privileges - most of PACA's events are open to PACA members only.
PACA conducts numerous education and training events during the year.
Choose concrete for your next parking lot project.
Streets built with concrete are built to last, consider concrete for your next project.
Concrete's strong, resilient and the choice for your next building or bridge.
PACA works with the National Ready Mixed Concrete Association (NRMCA) to convert your parking lot or building project to concrete without hurting your bottom line.
PACA drives a member-approved strategic plan to increase market share and engages specifiers and owners on the value of concrete in their projects.
This program provides free continuing education to the design and specifying communities. There are currently four courses available, ranging from 30 minutes to 60 minutes focused on the cement, aggregates and concrete industries. You'll receive a certificate of completion once you pass a quiz. The bookmarking feature allows you to leave the course and resume where you left off when you return.
Just how many tires get discarded every year? More than a billion globally; about 300 million in the United States. Recycling this many tires is an ongoing logistical challenge.
On top of that, there’s a backlog of tires that have piled up over the years. The EPA estimates that there are 2-3 billion old tires across the country. Fires are a threat, and standing water in the tires is the perfect breeding ground for mosquitoes. About 40 of 50 states now ban tires from landfills. Illegal dumping leads to fines and, potentially, incarceration.
The typical tire on a passenger vehicle weighs roughly 20 pounds. The average truck tire weighs triple that. An 18-wheeler travels about on tires weighing 100 pounds or more. Tires on the largest mining trucks are more than five feet wide and 14 feet in diameter. They weigh more than six tons each!
The bigger and more valuable the tire, the more likely it is to get recycled through retreading. Every year, about a third of America’s worn tires get retreaded. In fact, the tires on long-haul semis may get new tread as many as three times. Retreading helps the environment. According to the EPA, a semi-truck tire requires 22 gallons of oil to fabricate. Retreading only requires seven.
Multiply those figures by a billion, and that’s a lot of rubber.
Tire recycling processes take worn out tires and turn them into something useful. Shredding a tire reduces its volume to about a fourth of the original. The resulting rubber crumb gets used in a variety of ways, including in the concrete industry.
The Dual Drive Crackermill produces finely ground rubber using a dual roller approach. Variable speed corrugated drums increase the friction ratio to speed shredding. When desired, micromill wet grinding reduces sizes further. Finer CRM grades deliver enhanced dispersion and reaction rates, but they cost more.
Molectra’s process is a multi-step method for breaking down tires. First, the two steel beads get removed from the tire trim. Second, the tire is sliced into pieces. They get treated chemically to soften them and to remove contaminants. Third, a series of rollers separate the corded fibers and steel wires. Finally, the softened rubber gets granulated. It's possible to produce various sizes from fine powder to pea-sized particles. Heat is applied to the rubber particles to extract the softening chemicals.
There’s also a cryogenic process that uses liquid nitrogen to freeze shredded tire strips to about -112 degrees F. The brittle rubber passes through pinch rollers that shatter rubber surfaces while leaving the strips intact. Cryogenic processing readily separates the rubber from the steel wires and textile cords. This process is more costly, but it yields clean, small particles. The other components are easily recycled as well.
By contrast, pyrolysis destroys shredded tire pieces in a reduced oxygen environment heated to about 800 degrees F. The process yields tire-derived fuel (TDF), char, and synthetic gas. The TDF is a fuel appropriate for use in heating cement kilns.
Old tires benefit the concrete industry in various ways, including:
Alternate fuel
Aggregates and/or sand
Feedstock for graphene concrete additive
In turn, the concrete industry benefits the environment by reducing stocks of discarded tires.
A 2022 report analyzes the tire-derived fuel (TDF) market. According to one analyst, the global TDF market will exceed $510 million by 2031, representing a CAGR of 2.9%. In the United States, there’s increased use of this high BTU-value fuel with reduced emissions.
One California cement plant uses whole tires and pistachio shells to fuel kilns. Others use tires shredded into pieces 1-3 inches long.
However, there is a problem using rubber as an aggregate. Rubber aggregates absorb too much moisture compared to natural aggregates. Now, Australian researchers suggest a solution. Compress wet concrete to remove much of the moisture. The use of a rubber aggregate yields a 20% increase in tensile strength and a 97% gain in compressive strength.
Rubber is also used as an aggregate layer in road beds. It provides thermal insulation that inhibits frost penetration, reducing frost heaves.
Thanks to University of Houston researchers, old tires are now a source for graphene oxide. Flash heating of rubber tire waste yields the desired results. Ready mix plants can add a small amount of graphene oxide to produce graphene concrete.
In a "lab to slab" study, University of South Australia researchers deployed rubber tires ground to the consistency of sand. The fine crumb rubber replaces up to one-fifth of the sand used in ready-mix concrete. Rubber-reinforced concrete offers a host of advantages. Workability is equal to or slightly better than traditional concrete. It is more ductile, making it more impact resistant. It also delivers enhanced thermal and acoustic insulation, and it is tougher and more resilient.
Rubberized asphalt concrete (RAC) is a formulation that’s been around for more than 50 years. RAC delivers a durable, skid-resistant surface. It contains ground tire rubber, conventional aggregates, and a binder. The cushioning effect of the rubber reduces road noise by up to five decibels. Every paved mile keeps thousands of tires out of landfills.
The Pennsylvania Aggregates and Concrete Association (PACA) is your source for the latest industry news. Our team welcomes any question you may have about an upcoming concrete project. Please contact us at your convenience.
February 22, 2024
Proficient carbon calculations are increasingly important as “Buy Clean” legislation proliferates. New York and Colorado are among the states that now require carbon calcs for public projects. An estimated 40% of emissions are from the built environment. According to one estimate, the planet’s total building floor area will double by 2060. This makes the concrete industry a key player in the quest for net-zero emissions products and projects.
February 15, 2024
The Natural Resources Defense Council (NRDC) notes that cement production is “so carbon intensive that even though cement makes up less than 15% of concrete by weight, it accounts for 90% of concrete’s carbon footprint.” The use of fossil fuels to fire cement kilns is a key source of these carbon emissions.
February 08, 2024
In the quest for reduced greenhouse gas (GHG) emissions, everyone has a role to play. In the concrete industry, this includes everyone from manufacturers to contractors, and from trade associations to governments. Here is a review of some of the major initiatives impacting concrete’s sustainability.
February 01, 2024
Ordinary Portland cement (OPC) requires high-temperature calcination of limestone. It is possible to use various emissions-reducing pozzolans in concrete. Fly ash comes from coal-fired power plants. Ground granulated blast furnace slag (GGBFS) comes from steel mills. Another SCM is metakaolin derived from kaolin.
The program is delivered in one (1) module and it should take approximately 30 minutes to complete. You will receive a certificate of completion once you pass the quiz. The bookmarking feature will allow you to leave the course and resume where you left off when you return.