Evaluation of the suitability for use of ternary cements with carbonate fillers or calcined clays: concrete compositions subjected to de-icing salts

Abstract

The Belgian collective research centres for the cement industry (CRIC-OCCN) and the (road) construction sectors (BRRC and Buildwise) have been evaluating the suitability for use of new ternary cements since 2020 in the pre-standardisation project ‘NEOCEM’. The project focusses on CEM II/C-M (K-S-L) and CEM VI (K-S-L) cements as defined in EN 197-5:2021 with up to 20 wt.% of limestone or dolomite filler and aims to incorporate these cements in the Belgian national annex NBN B15-001 to the European standard EN 206. Complementary to carbonate fillers, calcined clays have also been investigated as supplementary cementitious materials (SCMs) in CEM II/B, CEM II/C-M and CEM V. An elaborated test program was carried out to evaluate the cement properties and the physico-mechanical and durability properties of the concrete mixtures.

In this paper, we will focus on the results obtained with concrete compositions satisfying to the requirements for an XF4 exposure class, implying the resistance against freeze-thaw attack in the presence of de-icing salts. Those compositions have a water to cement ratio of 0,45 and minimum cement content of 340 kg/m³ and were tested with and without air entraining agents.

The results obtained on fresh and hardened concrete will be discussed and compared in order to assess the technical feasibility (use of admixtures, mix design,…) and the durability of these concrete compositions obtained with alternative, low carbon cements with a view of possible application in the road construction sector.