GreenJams: Revolutionizing Construction with Low-Cost, Carbon Negative Concrete

Concrete is responsible for about 8% of global emissions and has a reputation as one of the "hardest-to-abate" sectors, as most green alternatives tend to come at a significant cost premium. For example, when I had looked at using Green Hydrogen in cement it cost 3-4x conventional alternatives. While many companies have identified low-carbon alternatives to aggregate (30-40% of emissions from concrete), very few solutions exist for low-carbon cement (60%+ of concrete emissions). Enter today's start-up GreenJams which has developed a carbon negative bio-concrete.

Like many hardtech Climate startups, GreenJams founder Tarun Jami put years of research into developing their solution. A civil engineer by training, he had seen many efforts into reducing the carbon footprint of concrete, including Hempcrete, which is widely used but limited in applications. Though they had initially started working with Hempcrete, they persisted to find a more all-purpose solution which could be used anywhere and for load-bearing (not just insulating) walls.

Enter AggrocreteTM?, which uses an alkali-activation-based chemistry which has been adapted to use biomass rather than traditional cementitious materialsaggregates. This breakthrough formulation allows GreenJams to create a concrete-like material using biomass. Combined with biological aggregates (or other low-carbon aggregates like waste fly ash and construction & demolition wastes), the concrete is actually carbon-negative as it turns carbon captured by plants into permanent structures.

I saw “concrete-like”, because the AggrocreteAgrocrete? actually has superior properties to traditional materials, in terms of strength:weight ratio, ease of construction, etc. For example, in traditional brick builders, “bond beams” (concrete beams to support in between block work) are required. By reducing the amount of supporting material such as joinermortar, the AggrocreteAgrocrete? blocks can actually help a project get finished faster and at lower cost. There is a further climate benefit as the insulative properties reduce the amount of heating and cooling required (also saving the occupants on their energy bills!).

Though the construction industry is notoriously slow to adopt innovation, GreenJams has been successful with 14 projects completed, with a 90% customer retention rate, indicating those that try it are impressed enough with the quality to continue to use it. They have already displaced 930 tons of carbon and can do 164,000 tonnes more in their pipeline alone.

GreenJams is continuing to innovate, moving from blocks to pre-cast products. They are currently developing additional pre-cast products and will soon add pourable/placeable readymix (similar to how most cement is sold today). The global market and need for low-carbon building materials is absolutely massive and I can’t wait to see their technology expand not just in India but all over the world.

GreenJams is an incredible example of how carbon negative can be achieved, all while improving both economics and quality of life. It is also a great example of how Indian innovators are breaking the supposed development vs. environment “trade-off”. Hopefully this story inspires many more.