Concrete is a fundamental element of the construction industry worldwide. Its most common composition of water, cement, and gravel dates back to the early 19th century, and since then, engineers and materials specialists have worked to improve its properties to make it stronger or even self-healing. However, its production continues to have terrible consequences for the environment: it is responsible for 9% of global CO2 emissions.
To counteract the emissions that are accelerating climate change, some are seeking alternatives that not only don't produce carbon dioxide, but are also capable of 'sequestering' it. Among them is Rick Fox, a former basketball player (winner of three NBA rings with the Los Angeles Lakers), who in 2021 co-founded Partanna, a sustainable building materials company that has just unveiled the first house built with carbon-negative concrete bricks.
This building in Nassau, Bahamas, where Fox grew up, is the first in a plan to build 1,000 sustainable homes for young people, a project undertaken by the government of the Caribbean nation. This initiative could be the starting point for the internationalization of these bricks, made from waste materials from other industries, offering a more durable and, above all, environmentally friendly product.
An ambitious project
“I entered the world of concrete out of sheer survival and the need to innovate in my own country,” Fox explains to The Verge. In 2019, Hurricane Dorian destroyed 75% of the homes on Abaco, one of the islands in the Bahamas, resulting in a true humanitarian catastrophe.
This sparked a quest that led him to join forces with American architect Sam Marshall, who had spent years researching and developing a new type of concrete that didn't use cement. Manufacturing this basic component of the material involves heating it to high temperatures in industrial kilns, which triggers a chemical reaction that releases large amounts of CO2 from the limestone.
This is how Partanna took its first steps, with an ambitious plan to finance itself through small investors and large investment funds, and a secret recipe for making the revolutionary concrete. The main ingredients of the formula to replace classic Portland cement are known: brine from desalination plants, which are very numerous in an archipelago like the Bahamas, and slag, a byproduct of the metallurgical industry.
According to its creators, the other major advantage of this sustainable cement is that it can cure at room temperature, eliminating the need for additional energy to heat the mixture. Furthermore, the natural and recycled binding ingredients can absorb CO2 from the air and sequester it within the bricks made from this material.
This means that in a house like the one already built, its walls continue to capture CO2 throughout its entire life cycle, and even beyond. If the structure is ever demolished, the material is able to retain the carbon dioxide and can be reused in the manufacture of new sustainable concrete. According to Partanna's calculations, the 116-square-meter pilot house has already captured as much CO2 as 5,200 trees per year.
Carbon-negative bricks
Among the main advantages of standard blocks made with Partanna concrete, Rick Fox's company highlights their greater durability, "guaranteeing long-lasting performance and reducing maintenance costs." They also mention superior compressive strength compared to traditional concrete blocks, which broadens their range of applications in construction.
However, the most striking feature of Partanna bricks is the use of brine. Thanks to this activating ingredient, this sustainable concrete gains greater strength when exposed to moisture and seawater, making it an ideal choice for coastal and marine projects. This is especially valuable in island nations like the Bahamas and cities like Nassau, which are threatened by rising sea levels.
To all this, Partanna's engineers have added an "innovative technology" (without offering further details), which "allows the creation of unique textures and designs, providing architects and builders with greater creative freedom in their projects," according to the product description on their website.
In terms of cost, the price of Partanna blocks is similar to that of traditional blocks, making them particularly attractive. The ultimate goal is to significantly reduce the carbon footprint of construction projects through "a viable, sustainable, and innovative solution to meet the growing demands of the industry.".
The next steps involve the construction of 29 new homes next year next to the pilot house in Nassau and a hub in Diriyah, Saudi Arabia, a country where 70% of drinking water comes from desalination plants. This generates enormous quantities of brine, which can be directly reused to manufacture thousands of Partanna's sustainable concrete blocks.
Source: https://www.elespanol.com/omicrono/.
