CO2 curing units that turn demolition debris into stronger recycled aggregate
TL;DR Aggrecure puts carbonation chambers at construction-and-demolition waste plants. Crushed concrete soaks up CO2, the gas fills its pores and you get a better aggregate for new concrete. Plants pay per tonne treated or share the price uplift, and verified carbon credits could become a second income.
India's new Construction and Demolition Waste Rules make large building projects use processed debris for 5% of their materials in 2026-27, rising to 25% from 2030-31, with separate targets for roads[1]. Recycled concrete aggregate is the obvious way to hit that, but builders don't trust it.
Why not? Old mortar stuck to the stone makes it porous, so it drinks up water and weakens the concrete.
Supply is thin too. CPCB guidance cites an estimate of 25–30 million tonnes of debris a year with only 5% processed, alongside other, lower estimates[2]. Plants do exist, like a 500-tonne-a-day plant at Burari in Delhi that has been running since 2009[2], but their output still has to win over engineers who would rather stick with fresh stone.
First, the regulatory bit - Aggrecure is an aggregate-treatment service. It improves a recycled product that must meet the quality standards named in the C&D rules[1]. It makes no carbon-removal claim until a third party has verified it.
An Aggrecure unit sits beside a plant's crushing line. Sized recycled aggregate goes into a sealed chamber, CO2 goes in under controlled humidity and pressure, and the gas reacts with the old cement paste to form stable carbonates. Published trials show water absorption falling by up to 18% and concrete strength gains of up to about 23%, though one flue-gas trial showed no gain at all[3]. Aggrecure tests each batch and hands the plant a quality certificate it can show builders.
The seed pitched CO2 mineralisation to fix cement's footprint, and I reframed it. Working inside cement plants needs a cement major's capital and consent. Treating debris aggregate is smaller, sells against a legal mandate and still locks away CO2.
The C&D recycling plant pays, either a fee per tonne treated or a share of the higher price its aggregate earns. Many plants run under municipal concessions, such as Ahmedabad's 300-tonne-a-day plant awarded on a 30-year PPP[2]. Builders and road contractors with targets are the end buyers. There's no public price for recycled aggregate in India, so you'll have to get it out of plants in interviews.
The C&D Rules 2025 were notified on 2 April 2025 and took effect on 1 April 2026, with utilisation targets that go up every year[1]. India's carbon market also lists a methodology for accelerated carbon mineralisation using reactive industrial waste, though it is still open for consultation and not approved[4].
There's no public figure for treated recycled aggregate in India. A CPCB estimate put available recycled concrete aggregate at about 1.8 million tonnes a year, based on an older and lower debris estimate[2].
The mandate is the real signal here - a share of material in every project above 20,000 square metres must come from processed debris[1]. Check current plant capacities city by city before you trust any total.
A Swiss carbon-removal firm binds captured CO2 into demolition concrete and mineral waste at 47 sites and sells removal credits[5]. A North American CO2-injection firm injects CO2 into fresh concrete at hundreds of plants worldwide but doesn't mention India[6]. Indian C&D plants crush and screen debris, and I couldn't find one that treats its output with CO2.
So the gap is a plant-side unit sold on aggregate quality first.
| Difficulty | Hard (62/100) |
| Starting capital | ₹2.5–4.5 Cr |
| Time to launch | 12–18 months |
The chemistry is published, so that's not the problem. The hard part is getting cheap, steady CO2 to a dusty debris yard and proving the quality gain on mixed Indian debris rather than neat lab samples, and then building measurement that a carbon verifier will actually accept. Municipal concession holders also move slowly.
Yes, this needs approvals, because you'll be adding a process unit and pressurised gas to a waste plant.
Building this outside India? The categories above usually have a local equivalent, so check with your own regulator.
Don't trust AI estimates of stored CO2 or concrete strength as final numbers. Those need lab tests and third-party verification.
Want to work out the AI layer for Aggrecure? Talk to Yash →
Here's what can go south -
I like this one for a founder with concrete-technology or cement-plant experience who can sell to municipal concessionaires. If you're counting on carbon credits to fund the business then it is not for you.
Before anything else, prove on one plant's real output that treatment lowers water absorption enough for a builder to accept higher replacement levels.
Plan for roughly ₹2.5–4.5 Cr, mostly for carbonation chambers, gas supply, lab testing and pilots at partner plants.
Yes, in practice. The partner plant needs registration under the 2025 C&D rules and an amended pollution board consent, and CO2 storage likely falls under PESO rules.
Yes, firms in Switzerland and North America already do versions of it. Check local waste, gas storage and carbon credit rules before you plan revenue around them.
The free Aggrecure validation kit has the line-by-line capital breakdown, the effort scoring, the C&D rule, gas-safety and carbon-market checklist, a 14-day validation sprint with pass/fail targets, a 90-day launch plan, 10 interview questions for plant operators and builders, and 5 assumptions to test. Download the kit →
Thinking about building Aggrecure or something close to it? The make-or-break work is sourcing cheap CO2 and proving the quality gain on mixed Indian debris, and that's the kind of thing I help founders work through. If you need a hand, you know where to find me. Talk to Yash →
For illustration only. Names are fictional and ideas hypothetical; sourced facts are real but may be out of date. Nothing here is legal, financial or professional advice, and Yash Khatri is not personally liable for any use of it. Read the full disclaimer.