Biochar in Concrete and Construction Applications

Biochar is becoming part of the material beneath our feet. Concrete footpath trials in Australia have put biochar made from coffee grounds and wood into everyday infrastructure, moving the idea from laboratory specimens to a surface people walk on.¹

For manufacturers, the interest extends beyond finding a home for biomass residuals. Biochar can contribute to strength, water behavior, and the use of conventional ingredients. Its value comes from the job it performs inside the material.^{2, 3}

Helping cement-based materials develop strength

Biochar’s pores and particles offer two useful routes into cement-based products. Pre-soaked biochar can carry water into a mortar mix and help support curing from within. Research on these mixes reported improved strength and water tightness under both moist and air curing.²

Fine particles offer another benefit. A wood-biochar mortar study found that small additions accelerated hydration—the reaction through which cement develops strength—and improved both early and 28-day strength. The resulting mortar also absorbed less water through capillary action.³

Softwood research adds to that picture. In a 2025 study, researchers turned spruce sawdust into biochar and used small amounts to replace cement in test pastes. The mixes developed higher compressive strength and absorbed less water through capillary action.⁴

Replacing sand with a useful carbon ingredient

At RMIT University, researchers converted spent coffee grounds into biochar and used it to replace part of the sand in concrete. In a tested mix containing coffee biochar in place of 15% of the sand by volume, compressive strength increased by about 29%.⁵

The same research program has moved into footpath and infrastructure demonstrations. That gives the work a practical next step: placing biochar-containing concrete in the field and following its performance over time.¹

Sand replacement and cement modification give biochar different roles. One substitutes for part of an aggregate; the other uses a small addition to change how the cement-based material develops. Together, the wood and coffee studies show promising roles for plant-based biochar in construction. Further research into different feedstocks and mixes could open more possibilities for concrete and other cement-based products.^{3, 5, 4}

Connecting performance with lower-carbon design

Biochar also places plant-derived carbon inside a durable product. RMIT’s later life-cycle work reported a lower carbon footprint for the coffee-biochar concrete scenarios it assessed, connecting the ingredient’s source with the concrete’s environmental performance.⁶

For a manufacturer, that creates an opportunity to develop the material and its carbon story together: what the biochar contributes, which ingredient it replaces, and how the finished product is made.

Choosing a material for your process

Wakefield supplies wood-based biochar in several forms. Premium Biochar provides a bulk starting material; Premium Biochar LM™ offers lower moisture; and CarbonMicro® 50 supplies a micronized powder.

We can discuss particle size, moisture, documentation, samples, and supply around your team’s material requirements. Visit Concrete & Asphalt to explore the options.