A new setup for rapid durabiity screening of new blended cements

Matteo Stefanoni;Ueli Angst;ELSENER, BERNHARD

2017-01-01

---

Abstract

In order to reduce CO2 emission and energy consumption of cement production substantially, the clinker content in the cements must be reduced. Blended cements, with high clinker substitution by a large variety of supplementary cementitious materials (SCMs), are appearing on the market. Today’s performance tests are time consuming, focus on transport properties for service-life modeling and neglect factors directly playing a role in corrosion (pH of the pore solution, alkalinity reserve). Thus a new way of testing blended cements that is both rapid and relevant for assessing corrosion performance is needed. We propose a new test setup that consists of small (8 x 8 cm2) and thin (6 mm) mortar samples instrumented with reference electrode, 5 steel wire electrodes and a stainless steel grid counter electrode, allowing performing both traditional and sophisticated electrical and electro¬chemical measurements. This innovative setup can be used to test any cement blend, w/c ratio and admixture content. Durability testing including the transport properties of the mortar and corrosion behavior of the steel can be performed both for chloride or carbonation induced corrosion. Specific applications that are envisaged are: - Fast durability screening of new blended cements in standard conditions; - Durability testing of already established blended cements in a variety of environmental conditions or testing of mixes for specific structures or environments; - Research on the mechanisms and controlling factors of steel corrosion in concrete. The users are cement producers, test laboratories, research institutions, standardization bodies, owners of new structures etc. The potential for application world¬wide is huge, especially because cement producers and users are still local and many different new blends have to be tested. The setup contributes to tackle the main future challenge of the building industry: to guarantee long-term durability of reinforced concrete infrastructure with minimum amount of clinker in the cement.