In building masonry projects, the bonding quality between mortar and bricks is directly related to the stability, integrity, and durability of the masonry structure. Once problems such as poor adhesion, hollowing, or peeling occur, they may lead to wall cracking, water seepage, and even potential structural safety hazards. Based on years of industry experience, Shandong tile adhesive manufacturers provide a detailed analysis of the key factors affecting the bonding between mortar and bricks as follows:
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- Insufficient mortar strength grade and workability: Low-strength grade cement mortar is one of the common causes of bonding problems. Such mortar has poor workability (fluidity and water retention), leading to great resistance when construction workers spread it with large shovels or trowels, making it difficult to achieve uniform application. This results in tiny cavities between bricks and mortar, which not only reduces the filling fullness of the mortar but also decreases the bonding contact area, ultimately weakening the overall bonding strength.
- Inappropriate moisture content of bricks: When using dry bricks for masonry, the bricks, due to their strong water absorption, will quickly absorb moisture from the mortar, causing the mortar to dehydrate and set early. The loss of moisture not only affects the normal hydration reaction of the mortar and reduces its own strength but also prevents the formation of an effective bonding layer at the interface between bricks and mortar; at the same time, the dust and debris attached to the surface of dry bricks form a natural isolation layer, further hindering the bonding and integration of bricks and mortar.
- Mismatch between mortar spreading process and construction rhythm: When using the mortar spreading method for masonry, if the mortar spreading length is too long while the construction rhythm is slow, a large amount of moisture in the laid mortar will be absorbed by the underlying bricks before masonry. This causes the mortar to lose its original fluidity and bonding activity. When subsequent bricks are laid, the mortar cannot fully adhere to the brick surface, eventually resulting in bonding failure between the brick layer and the mortar.
- Improper construction process of fair-faced brick walls: To save the joint scraping process, some constructions adopt the large shrinkage mortar spreading method when building fair-faced brick walls, resulting in the shrinkage depth of the masonry joints exceeding 20mm. This approach not only directly reduces the filling fullness of the mortar in the brick joints and decreases the effective bonding area but also increases the construction difficulty of subsequent joint pointing. If the joint pointing is not dense, it may also lead to rainwater infiltration, further damaging the interface bonding performance and affecting the integrity and durability of the wall.
