Enable sustainable water reuse by utilizing ettringite as a value-adding mineral addition in cementitious concrete

Purpose and goal

This project aims to solve the bottleneck problem in the new technology for better wastewater treatment. The aim of the project is to experimentally investigate the feasibility of using the by-product ettringite as a value-adding mineral addition in cementitious concrete. The results show that this by-product can be used in concrete with an addition of up to 10% of the cement weight without impairing the properties of the concrete. This means that the by-product can be used as a zero-carbon addition in concrete. Therefore, the goal of this project was, to a great extent, fulfilled.

Expected results and effects

A methodology based on the principle of constant volume of cement hydration products was developed for proportioning of concrete with the addition of ettringite as a part of hydration products. This methodology can help concrete manufacturers to proportion concrete with the by-product ettringite as zero-carbon addition instead of landfilling and therefore promote the application of the new technology for better wastewater treatment, as expected effects in the future to contribute to Agenda 2030, goals 6.3; 12.2; 12.4 and 12.5.

Planned approach and implementation

This project was mainly based on experimental approach together with cement chemistry analyses. The project was carried out in close collaboration between an academic partner as a "problem solver" and two industrial partners, one from the wastewater treatment sector ("need owner") as supplier of the by-product and another from the construction sector as users of the by-product. Three participants in the constellation have collaborated in very good ways in the project, which has led to a satisfactory fulfillment of the goal.