Lime as an Anti-Plasticizer for Self-Compacting Clay Concrete.

Gnanli Landrou,Coralie Brumaud,Frank Winnefeld,Robert Flatt,Guillaume Habert

doi:10.3390/ma9050330

Gnanli Landrou, Coralie Brumaud + Show 3 more

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https://doi.org/10.3390/ma9050330

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Abstract

This paper focuses on the modification of clay properties with inorganic additives to deflocculate and flocculate inorganic soil for the development of a material that would be as easy to use as the current concrete products, but with a much lower environmental impact. Considering that the rheological behaviour of clays is controlled by their surface charge, we first introduce potential determining ions to deflocculate the clay particles and to reduce the yield stress of the earth material. Their efficiency is characterized using zeta potential measurements and rheological tests. We then achieve the flocculation of clay particles by using natural minerals that slowly dissolve in the interstitial liquid and ultimately precipitate calcium silicate hydrate (C–S–H). The precipitation products are identified by X-ray diffraction and the consequences of this delayed precipitation are followed by oscillatory rheometric measurements. Finally, it is suggested that in this process, C–S–H precipitation is not used as a binding vector but as an anti-plasticizer that removes the inorganic dispersant additives.

Highlights

Traces of earthen architecture date to 10,000 years ago, and this building material technique is still used in most climates and societies [1]
The water to solid ratio is equal to 0.5, which allows for an initial material that is sufficiently thick to evaluate the efficiency of admixtures
Since the yield stress of the constitutive paste controls the stability of the material [13,41,42], this very low yield stress could lead to static segregation issues

Summary

Introduction

Traces of earthen architecture date to 10,000 years ago, and this building material technique is still used in most climates and societies [1]. Without transport and with infinite recycling possibilities, earth is among the building materials which have the lowest environmental impact [2,3]. Earth construction is currently under strong development, likely due to environmental concerns. This development is limited because the conventional earth construction techniques are both time-consuming and labour-intensive. Cement is an incredibly easy-to-use material but has a significant environmental impact [5]. Substantial engineering and scientific efforts have been invested to improve the understanding and processing of cement-based concrete, but no or very little engineering improvement has been made in the case of earth

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