Milk and sugar with your cement?

Researchers in Melbourne are trialling adding coffee grounds to concrete to eliminate waste. Each year Australia produces around 83,000t of ground coffee and chaff, the majority of which ends up in landfill producing methane and other greenhouse gases as it decomposes. 

A team of scientists at the Royal Melbourne Institute of Technology (RMIT) are now trying to put the surplus coffee grounds to better use, adding them to cement, water, gravel and sand to produce cement. According to the Washington Post, the coffee grounds are cooked at 350˚C with a little oxygen, a process known as pyrolysis. The resulting substance, called biochar, is then added to the cement mixture to replace 15 per cent of the sand. 

Spent coffee grounds make up a significant proportion of the total organic waste going to landfill in Australia. “This leads to the production of methane gas, which contributes significantly to climate change,” the RMIT scientists wrote in their paper. “Therefore, there is an urgent need to discover various recycling solutions that can help in diverting this waste from going to landfills into commercial applications.”

Using organic matter in concrete production in this way also reduces the demand for sand and sand mining, adding to the circular economy.