The first 100% circular and CO2-negative building blocks

Concrete Agglomerates Gubbels in Maasmechelen is a third-generation family business that makes mechanically produced stackable concrete blocks for temporary or permanent structures. These conquered the market under the name 'Masterbloc'. Its revolutionary further development, 'Carbstone', builds on the strength, reliability and ease of placement of the original concrete product but adds a number of unique ecological advantages by omitting cement.

Initially, the company started producing concrete blocks for various applications. In the late 1990s, it launched the 'Masterbloc' on the market. "Why make something difficult if it can be simple?", they must have thought at Gubbels when designing the 'Masterbloc'. Entirely in the spirit of a well-known Danish toy manufacturer, a concrete stacking block was developed with lugs and ridge holes. The mechanical production process makes these stacking blocks stronger and more precise than similar blocks cast in hand molds. As a matter of fact, Gubbels is the only one using the mechanical production process. There is only a minimum clearance of 2.6 mm between ridge and ridge hole, allowing the blocks to interlock more firmly and withstand higher shear forces. No recycled materials can be used in mechanical production, making 'Masterbloc' the purest on the market. 'Masterbloc' already exists in several versions, including masonry bricks, masonry blocks, glue blocks, precast walls and 'Soundblox'. The newest version, 'Carbstone,' adds an ecological dimension. 'Carbstone' is already currently available as a masonry brick and soon as a stacking block.

Reducing CO2 emissions is a hot topic in today's construction world. With the new 'Carbstone', Gubbels takes this one step further. She has managed to turn low-CO2 into CO2-negative by excluding cement from the production process. After all, cement is responsible for over 10% of global CO2 emissions.

The concrete for the production of "Carbstone" is not bonded with cement but with carbonated limestone and slag from the metal industry. The CO2 is actively added during the production process. It remains in the product as a binding agent, eliminating the need for cement. Gubbels developed this unique technology with its partner Orbix. The result is a masonry brick or stacking block that is even stronger than one made with cement. 'Carbstone' is the ultimate weapon in the fight against CO2. These building blocks are completely Circular, Cement-free and CO2 negative. After processing, the building blocks even absorb CO2 which also further increases their carrying capacity. At the end of their life cycle, the bricks or blocks can be crushed and only sand and gravel remain. In terms of positive properties, such as high compressive strength, this new Carbstone is almost identical to concrete but without the ecological disadvantages.

Managing Director Björn Gubbels: "I would like to quote some figures that illustrate the importance of our ecological approach. When delivering one truck of ordinary concrete masonry bricks or stacking blocks to the construction site, we have to deal with 3 tons of CO2, mainly due to the production process. The same truck with 'Carbstone' cement-free products has already captured these 3 tons of CO2 forever during the production process, so the emission into the atmosphere is zero. In other words, for the same volume delivered, 'Carbstone' saves a net 6 tons of CO2 per truck."

Gubbels has long manufactured the "Soundblox" stacking blocks under license from Soundless Acoustics. These acoustic concrete or argex blocks feature two vertical slots and a hollow space that maximize sound absorption. Now the 'Carbstone' products are also available in 'Soundblox' version, enabling Gubbels to kill two birds with one stone: reducing harmful CO2 emissions and disturbing noise pollution. Carbstone' thus provides an answer to two hot topics in today's construction sector.