The Real-World Benefits of Low-Carbon Concrete: Stories, Data, and Climate Impact

Late in 2024, San Jose resident Jeff W. had a growing problem: his sidewalk was cracked, lifted and clearly hazardous. Someone could get hurt and he'd be responsible. Like thousands of other homeowners across the city each year, Jeff was thrust into an unexpected civic obligation when he started noticing his sidewalk separating in two places. He affixed warning tape to the damage, but he knew that wasn’t enough. While most residents receive a letter from the city telling them to fix their their damaged sidewalks, Jeff figured he'd deal with it now, before he got notified. A few weeks later a city inspector arrived, marked the damaged sidewalk and the adjoining parkway, and gave him more bad news: the large tree would likely have to be removed too. He didn't expect the additional cost of the parkway or the possibility that he'd lose one of his beloved trees. 

But then something unusual happened.

He was contacted by  a local initiative called Pave the Way San Jose. The premise was simple: what if this annoying, required repair could also be an act of climate action? What if the concrete used to fix his sidewalk could help reduce greenhouse gas emissions? Jeff was intrigued—and skeptical.

"Concrete contributes to climate change?" he asked. It seemed like a stretch. After all, it was just a sidewalk.

That’s when he met H.B. Mok, founder of Pave the Way San Jose. H.B. wasn’t a contractor, but an advocate. He explained that traditional concrete is responsible for more than 8% of global CO₂ emissions, largely due to the production of cement, its key ingredient. But there was another option: low-carbon concrete, already approved by the city and available at no extra cost.

Jeff was no stranger to innovation. Now retired, Jeff had worked at a Silicon Valley software company for 36 years, so new technology always interested him. After listening and asking questions, he was eager to try low-carbon concrete and do something good for the planet he was leaving to his grandkids. 

And with that, he became the first resident in San Jose history to use verified low-carbon concrete for a residential sidewalk repair.

The process wasn’t without challenges. There were scheduling hiccups, weather delays and concrete mix logistics. But with support from Calafia Pacific (his contractor), Central Concrete (the low-carbon concrete supplier), the San Jose Department of Transportation, and the team at Pave the Way San Jose, Jeff's sidewalk was successfully repaired. Even better, the city decided he could keep his tree.

The finished job covered just 76 square feet. But the ripple effects were immediate: 63 kilograms of CO₂ saved from his job and a contractor newly committed to using low-carbon concrete on commercial jobs, starting with a local In-and-Out restaurant. Jeff told his landscaper who is now looking to adopt the low carbon material in future projects. Neighbors asked questions and Jeff shared what he had learned.

"You can do this too," he told them.

His small decision became proof that with the right support and just a bit of awareness, everyday repairs could become climate solutions. That climate action isn’t always about sweeping legislation or global treaties. Sometimes, it’s about the patch of pavement beneath your feet.

Jeff didn’t just fix a sidewalk. He paved the way.