Concrete Cancer ll, New Podcast, License Compliance

When Concrete Gets Cancer: Understanding Pool Structure Deterioration

As pool professionals gear up for another season, there's one silent threat that could be undermining every concrete pool structure in your service route: concrete cancer. While this term might sound alarming, understanding this phenomenon is crucial for anyone in the pool industry who wants to provide lasting value to their clients and avoid costly structural failures down the road.

Concrete cancer isn't just a catchy term—it's a real deterioration process that affects countless pools across the country. Just like its biological namesake, early detection and proper treatment are essential for managing this destructive force that can compromise the structural integrity of concrete pools.

The Science Behind Concrete Cancer: Two Destructive Mechanisms

Concrete cancer encompasses two primary deterioration mechanisms that work silently to destroy pool structures: alkali-silica reaction (ASR) and rebar corrosion. Both processes can devastate concrete integrity over time, making it essential for pool professionals to understand how they work.

ASR is a chemical reaction that occurs between alkalized cement and reactive silica in certain aggregates. When water is present, these components form gel. This gel absorbs water and swells, causing internal stress in the concrete. And over time, that leads to cracking, spalling, and a significant reduction in the structural integrity of those materials.

— Rudy Stankowitz, Talking Pools Podcast

The alkali-silica reaction creates a distinctive pattern of damage that experienced pool professionals learn to recognize. The primary symptoms include map-like cracking patterns across concrete surfaces, expansion and deformation of concrete elements, and surface discoloration accompanied by white gel-like deposits that seep from cracks.

For ASR to occur, three critical factors must be present: reactive silica in aggregates, sufficient alkalies in the cementitious material, and moisture acting as a catalyst. In pool environments, that third factor—moisture—is obviously abundant, making pools particularly susceptible to this type of deterioration.

Rebar Corrosion: The Hidden Destroyer

While ASR attacks the concrete matrix itself, rebar corrosion targets the steel reinforcement that gives concrete its strength. This process occurs when steel reinforcement becomes exposed to corrosive agents like oxygen, chlorides, and carbon dioxide that penetrate through cracks or porous concrete.

The oxidation process creates rust (iron oxide) that expands in volume, putting tremendous pressure on surrounding concrete and causing spalling and structural damage. Pool professionals should watch for several warning signs: cracking and delamination around rebar locations, rust stains on concrete surfaces, spalling and loss of concrete cover, and reduced structural capacity due to diminished rebar cross-section.

Here's where water chemistry plays a role in watching that pH. Water is essential for the production and curing of concrete. It also plays a role in the deterioration of the concrete. For ASR, water activates the alkali-silica reaction and fuels the expansion of the gel. For rebar corrosion, water transports chlorides, oxygen, and other corrosive agents to the steel reinforcement.

— Rudy Stankowitz, Talking Pools Podcast

This connection between water chemistry and concrete deterioration underscores why proper pool chemistry maintenance isn't just about swimmer comfort—it's about protecting the structural investment that the pool represents.

Prevention Strategies: Stopping Concrete Cancer Before It Starts

The most effective approach to dealing with concrete cancer is preventing it from occurring in the first place. For pool builders and renovators, this means implementing specific strategies during the construction phase.

Preventing ASR requires careful attention to material selection. This includes using non-reactive aggregates, conducting petrographic analysis and accelerated expansion tests to identify potentially problematic materials, and incorporating supplementary cementitious materials (SCMs) like fly ash, slag, or silica fume. Low-alkali cement with an alkali content below 0.6% is recommended, along with moisture control through water-repellent sealers, membranes, or waterproofing admixtures.

For rebar corrosion prevention, the focus shifts to creating barriers and improving concrete quality. High-quality concrete with low permeability limits the ingress of chlorides and moisture. Protective measures for rebar, such as epoxy-coated or galvanized reinforcement, provide additional resistance. Increasing concrete cover thickness creates a longer diffusion path for corrosive agents, while cathodic protection systems can reduce the electrochemical potential that drives corrosion.

Treatment and Repair: When Prevention Isn't Enough

Despite best prevention efforts, concrete cancer can still develop in existing pools. When this happens, proper repair techniques are essential for restoring structural integrity and preventing further deterioration.

Repairing ASR damage begins with removing all affected concrete to eliminate areas where the reaction continues. Surface treatments like sealers or membranes can limit future moisture ingress, but replacement efforts should involve low-alkali, high-performance concrete with non-reactive aggregates. To relieve stress caused by gel expansion, joints or slots can be cut into the concrete.

For rebar corrosion repairs, all cracked and spalled concrete must be removed to expose corroded reinforcement. The rebar is then cleaned using mechanical or chemical methods, followed by corrosion inhibitors or epoxy coatings. Severely corroded rebar may require replacement or supplementation, and high-quality repair mortars or concretes should restore the structure with proper bonding between repair materials and existing concrete.

Industry Innovation: Hope on the Horizon

The concrete industry continues to develop innovative solutions that offer hope for the future of pool construction and repair. These advancements could revolutionize how the pool industry approaches concrete cancer.

Recent advancements in science and construction technology offer new ways to combat concrete cancer, which is great for the pool industry because there is hope. There are solutions out there. We just haven't adopted them in the pool industry as of yet.

— Rudy Stankowitz, Talking Pools Podcast

Some of the most promising developments include self-healing concrete that incorporates microcapsules or bacteria to automatically seal cracks when exposed to moisture. Nano coatings provide ultra-thin layers that enhance water repellency and reduce chloride penetration. Structural health monitoring systems use embedded sensors to track cracking, moisture levels, and rebar corrosion in real-time, while high-performance repair materials like polymer-modified mortars and fiber-reinforced composites offer more durable repair solutions.

The Importance of Professional Mentorship and Compliance

Beyond technical knowledge about concrete cancer, the pool industry faces ongoing challenges around professional standards and licensing compliance. The podcast discussion highlighted the importance of approaching these issues with a mentorship mindset rather than a punitive one.

Maybe the correct solution is just to reach out, say hello, and offer to take that person by the hand. Live more in the culture of lifting one another up instead of bashing one another against the wall. That would be my solution, I think... Most valuable thing you can do for the pool industry is take on that role. Mentor.

— Rudy Stankowitz, Talking Pools Podcast

This approach recognizes that advancing industry knowledge—whether about concrete cancer, proper licensing, or best practices—requires professionals who are willing to share their expertise and guide others toward better practices.

Moving Forward: A Proactive Approach to Pool Longevity

Understanding concrete cancer represents just one aspect of providing comprehensive pool services, but it's a critical one that directly impacts client satisfaction and long-term costs. By recognizing the signs of ASR and rebar corrosion, implementing prevention strategies, and staying informed about new technologies, pool professionals can offer greater value and build stronger relationships with their clients.

The key takeaway is that concrete cancer, while serious, is manageable through proper knowledge, prevention, and treatment. As the industry continues to evolve and adopt new technologies, the tools for combating these destructive processes will only improve. Until then, education, vigilance, and proactive maintenance remain the best defenses against concrete cancer in pool structures.

Regular inspection and maintenance, combined with proper water chemistry management, can significantly extend the life of concrete pools while minimizing the risk of expensive structural repairs. For pool professionals committed to excellence, understanding concrete cancer isn't just about technical knowledge—it's about protecting their clients' investments and maintaining the integrity of the structures they're trusted to care for.

Episode Chapters

• 00:00 Introduction and Industry Updates
• 05:30 Licensing Compliance Discussion
• 12:15 Concrete Cancer Research Update
• 18:00 Understanding ASR (Alkali-Silica Reaction)
• 25:30 Rebar Corrosion Mechanisms
• 32:45 Prevention Strategies
• 40:20 Treatment and Repair Methods
• 48:00 Future Technologies and Solutions