Historical and Scientific Investigations into the Use of Hydraulic Lime in Korea and Preventive Conservation of Historic Masonry Structures

Abstract

In addition to non-hydraulic lime, natural hydraulic lime (NHL) is a material widely used to repair and restore historic buildings. In Korea, although lime mortars have been used as important building materials for thousands of years, the sharing of information and technology with other countries has been relatively inactive. While not recognizing the suitability of NHL as a repair material, undesirable materials such as Portland cement have often been selected due to their high strength, ease of use, and hydraulicity, but unfortunately, this has resulted in the irreversible damage of existing elements, especially in historic masonry structures. This study aims to emphasize the need for hydraulic lime for the sustainable preservation of Korea’s architectural heritage. To justify its use, historical and scientific investigations were conducted. By reviewing literature written in the 15th century, it was found that dark limestone was used to manufacture building lime. Based on this, the chemical compositions of different-colored limestone were experimentally analyzed, and significant evidence was found that dicalcium silicate was formed in the quicklime manufactured by calcining blue-green and green-black limestone. Prior to the 19th century, it would have been impossible to record the chemical compositions of various types of limestone, except for visual observations such as color differences. Fortunately, this important information was recorded in royal documents and has been handed down to the present day. Thus, knowledge from 500 years ago could be scientifically interpreted using the latest technology. The link between the historical record and the experimental results shown in this study can contribute to the selection of a suitable material. This is a method for the preventive preservation of historic masonry structures, as it can significantly lower the possibility of future damages caused by efflorescence and freeze–thaw.

The Influence of Dry Hydrated Limes on the Fresh and Hardened Properties of Architectural Injection Grout

“…The results in Table 1 and Table 2 show that the CH-CL90 lime contains the highest portlandite content and a higher purity compared to the two limes from Slovenia. The highest content of impurities can be found in the SI-CL90 lime from Slovenia, which also contains the highest MgO content that can negatively influence the slaking process of the quicklime and thus the quality of the hydrated lime [ 17 ]. All these hydrated lime products can be characterised as high-calcium lime (Ca(OH) 2 ≥ 90%) with traces of CaCO 3 (≤6% by mass) [ 32 ].…”

“…The main impurities consist of silica, alumina, iron and magnesium (in high calcium lime) [ 16 ]. Magnesium oxide (MgO) is disadvantageous in high calcium lime as it affects the reactivity of the quicklime [ 17 ]. Additionally, the four impurities listed influence limestone hydraulicity calculated using the cementation index (CI), developed by Eckel [ 18 ].…”

Effect of Fibrillated Cellulose on Lime Pastes and Mortars

“…Additionally, slaked lime partially re-absorbs the carbon dioxide emitted during the production process as it recarbonates over its in-use phase, thus resulting in lower net carbon emissions [17,18]. Moreover, lime can as well be used for the retrofit of historical buildings [19], since it is well known that cement-based mortars are not chemically and physically compatible with aged and porous materials [20]. In this context, the use of fibres can indeed help increasing the flexural strength, avoiding crack propagation in mortars and plasters, eventually delaying the need for maintenance interventions.…”

Experimental Investigation of Traditional Clay Brick and Lime Mortar Intended for Restoration of Cultural Heritage Sites

“…Cement mortar has recently been used as a substitute for lime mortar when retrofitting masonry cultural heritage sites, because of its durability and higher strength [9][10][11][12]. In addition, several studies have investigated the performance of eco-friendly materials that could be used to preserve and enhance such structures [13][14][15][16].…”