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.
Construction aggregate includes a range of particulate materials - ranging from coarse to medium grains - including sand, gravel, slag, crushed stones, and recycled concrete. These materials are mixed in with concrete to give the end product a strong and durable finish.
Construction contractors and customers alike, look for affordability and strength above all else. A world of difference can be seen in both these factors when the right concrete aggregate is utilized. One viable aggregate that comes in multiple sizes and scales is hardened concrete.
As buildings, roads, bridges, and other structures are demolished every year, hundreds of thousands of tons of debris is generated. As the world moves towards saving the environment, and governments offer tax rebates to those investing in fuel-efficient technologies in an effort to reduce their carbon footprint; recycling this debris is the perfect way for any contractor to save the environment and their expenses, all while ensuring strength in the foundation of their new structures.
The purpose of aggregate is to increase the volume of a concrete mix while ensuring minimum air is trapped within the structures. The material that makes up the aggregate is of different shapes and sizes, allowing them to fit snugly with one another.
The larger, coarser aggregate particles settle together to constitute a skeletal structure for the mixture. Smaller particles serve as fillers between the spaces between these larger particles, and in turn particles even smaller rush to fit into the gaps between the fillers.
Finally, the smallest gaps within the aggregate are filled with cement particles, holding the whole structure together. This property shows that the better the size distribution provided in aggregate, the stronger a concrete structure will be; however, it is necessary to keep in mind the optimum amount of recycled aggregate that should be added to the concrete mix. Changes in the blend can lead to an overall decrease in the strength of your structure, which is why recycled aggregate remains most appropriate for bases and sub bases.
Crushed concrete has been in use since the ancient times, only to be integrated with gravel, sand, and cement to ensure durability. The practice was first recorded in the 1860s. US construction companies were reluctant to use the technique at first, since crushing cured concrete proved to be much more cost-intensive in terms of labor.
However, in the 1970s, when the construction era was at its peak, landfills refused to accept broken concrete, since it had no recyclability, and took up too much space. One landfill, on the other hand, continued accepting concrete dumps, crushing it with the help of bulldozers and rollers, and reselling it as aggregate.
After a number of successful projects, construction companies confirmed that not only did recycled concrete offer equal durability and strength in new concrete; it also had a much lower impact on the environment.
With advancements in construction technology, recycled concrete aggregate has seen further developments, making it much more refined and cost-effective.
Thanks to increased environmental laws, and the desire to keep construction costs down, recycled concrete aggregate has found quite a following. Due to its assimilated nature, it provides even higher economies of scale then those possible with the use of regular aggregates.
Demolished concrete is collected from sites and put through crushing machines. These machines can reduce larger rocks to smaller rocks, gravel, or even dust! The concrete can be refined for rebar, wood, or other metal chunks before being added to these machines. There are several types of crushers:
Most of these crushers use an impact force, or a ‘tumbling’ mechanism to break down larger stones.
The water absorption value – or penetrability – of recycled aggregate is 7.5%, much higher than the minimum (3.7%) required by the Washington State Department of Transportation’s (WSDOT) construction division. This higher rate is attributable to gravel’s own absorption rate, added to that of the paste.
Different portions of the recycled aggregate hold varying measures of specific gravity, characterizing the cured cast’s strength, compression-resistance, and modulus elasticity. However, using a recycled aggregate of more than 65% can impact the mix’s durability significantly, reducing its physical properties tenfold. The optimum amount blended in with the concrete should be 35%.
Some experiments have shown that the recycled aggregate is durable, no doubt, but not as sturdy as natural coarse aggregate. However, to tackle the lack of strength, you can treat the mix with materials such as fly ash.
Recycled concrete aggregate presents numerous benefits:
As with everything, the aggregate also presents certain risks that constructors should be aware of:
Recycled concrete aggregate offers many diverse advantages, among the most prominent are safety and durability. However, keeping in mind the complications posed by the use of concrete aggregate in overlays, it is highly advised to utilize recycled concrete for bases and sub bases.
If you are looking for a sustainable solution for your construction needs, you don’t need to look any further than Specify Concrete, a safe and reliable construction company brought to you by the Pennsylvania Aggregates and Concrete Association (PACA).
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.