|
|
Identifying the Problems and their Causes
3. Deterioration of the Bonding Material
|
|
The decay of the original bonding material is apparent throughout the entire wall, both on its exterior sides and in the core of the wall. Water and vegetation are the two principal causes which exacerbate the weathering process of the bonding material.
Disintegration of lime-based bonding material in the outer sides of the wall. The wall is built of coarsely dressed stones. The bonding material assists in distributing the load and connecting the stones; hence its importance. In certain regions the disintegration of the bonding material is superficial; however, it allows water to seep into the wall and vegetation to take root (Fig. 21). Elsewhere the disintegration of the material is deeper and joints that are 6-8 cm wide and 30-40 cm deep are devoid of bonding material. This condition is likely to damage the stability of the outer facades or the stability of the vaults and arches in the sentry posts.
Soil-based bonding material that is being washed from the core of the wall. In the current survey no invasive examinations were conducted in the core of the wall. Nevertheless, the problem is typical and known to occur in walls that have two sides and a soil-based debesh core. When the bonding material is washed from the core of the wall the debesh turns into a "bulk of stones" that exerts pressure on the outer sides of the wall.
The required treatment calls for preventing water from seeping into the wall. It is recommended that the joints be pointed up with a lime-based bonding material and that routine conservation maintenance be performed, the essence of which entails removing vegetation and filling in the joints with lime-based bonding material.
Identifying the Problems and their Causes > 4. Cracks
|
|
|
| 21. Disintegration of bonding material |
|
 |
 |
|
|
| Websites, text and photos © Israel Antiquities Authority |
Powered by teti-tu |
|
|
