## 4 Conclusions  
This study investigated the material properties of different types of mortar and their effects on masonry specimen's performance. The research results can contribute to the separation and maintenance practices used for masonry cultural heritage sites. Two kinds of mortar (quick lime lumps, powdered hydrated lime) were used at four different lime:sand:cement mixing ratios. The experiments included material tests of the mortar and brick and performance tests of masonry specimens. The following conclusion can be drawn from the experimental results.  
1. In the material tests, the addition of white cement resulted in almost no noticeable enhancement of mortar strength. However, in the masonry specimens, this effect was more pronounced. This can be interpreted to mean that the bonding between mortar and bricks, which is a critical factor affecting the masonry's behavior, was stronger with additional cement in the mixing ratio.
2. For each type of mortar (LL and PL), mixtures with white cement exhibited superior behavior in terms of compressive strength and diagonal shear strength compared to non-cement mixtures. However, this effect was barely observed in triplet shear tests, where the change in shear strength of most of the masonry specimens was minor (below 0.11 MPa), which led to prompt failure by detachment of either the mortar layer or the mortar bed joint and bricks.
3. The results also implied that the white cement had a greater effect on PL mortar than LL mortar.The compressive strengths of the LL-3 and PL-3 masonry prisms were 11.38 MPa and 15.39 MPa, respectively, and the PL-3 compressive strength was 35.2% greater than that of LL-3, while the diagonal shear strength of the masonry panels were 0.242 MPa and 0.284 MPa, respectively. Therefore, the mixing ratio of PL-3,  
Figure 19: Diagonal compression test results. (**a**) Shear strength, (**b**) strain–stress curve.  
Figure 20: Failure mode diagonal compression test.  
which provided the most favorable performance among all ratios, can be considered for the repair and maintenance of masonry cultural heritage sites. Future research can investigate further effects of different ratios of added cement.  
The lime mortar generally exhibited minor strength in specimens, compared to other alternative materials such as cement mortars. However, for most masonry cultural heritage sites, lime mortar is considered a compatible material that associates well with the original substrate. To further evaluate the practical application of lime mortar to such structures, additional studies on material properties and masonry specimens and mixing ratios will be required.  
Conceptualization, K.L. and G.L.; Supervision, K.V.A.P.; Formal analysis, J.H.P. and C.H.L.; Writing--original draft, G.L.; Writing--review & editing. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Research Institute of Cultural Heritage, Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education.  
Not applicable.  
This research was funded by the National Research Institute of Cultural Heritage (grant No. 1555001037 to NTIS), This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education(NRF-2020R1A6A3A13074670).  
The authors declare no conflict of interest.