The Correlation of Workability and Mechanical Strength in air lime binders with different aggregates and pozzolan

Abstract

In this study are investigated two air lime binders common in conservation practice. The first one is a commercial air lime, emerging from dry slaking, which was left to age for 4 months. The second is a natural quicklime emerging from the burning in a traditional lime kiln from Mariestad, Sweden. Their workability, compression and flexural strength have been tested in correlation with the addition of rounded natural aggregates, angular (crushed) aggregates and pozzolan. The main aim of this study is to seek for the optimal interaction between the aggregates and these two binders with and without the addition of pozzolan. This study showed that the commercial material was more workable than the natural quicklime and it had inferior mechanical performance. With the addition of pozzolan the mechanical performance was improved for both binders. The natural quicklime from Mariestad, after slaking (hydration) was less workable compared to the commercial material, and the angular aggregates significantly worsened its workability. It became more workable and performed mechanically better with the addition of pozzolan, independent from the aggregates´ shape.