1. Improper mortar mix ratio
The mortar mix ratio has a direct impact on the performance of thermal insulation mortar. If the ratio of raw materials such as cement, sand, and RDP is not appropriate, the strength and adhesion of the mortar will be insufficient, thereby increasing the risk of cracks. For example, if the amount of cement is too much, the shrinkage of the mortar will increase, or the RDP is used improperly, resulting in insufficient toughness of the mortar and easy cracking.
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2. Cement quality problems
Cement is an important bonding material in thermal insulation mortar. If the quality of cement does not meet the requirements, such as insufficient strength grade, poor activity or excessive impurities, it will lead to poor mortar adhesion and easy cracking. The hydration process of cement determines the strength and stability of the mortar, and poor quality cement will accelerate the appearance of cracks.
3. Influence of temperature and humidity
External environmental conditions have a great influence on the performance of thermal insulation mortar. During the construction process, too high or too low temperature, too high or too low humidity will affect the hardening process of the mortar, thereby increasing the probability of cracks. In hot weather, water evaporates too quickly, causing the mortar surface to shrink and form cracks; while in low temperatures, the cement hydration reaction of the mortar is slow, which will also affect the strength of the mortar and increase the possibility of cracks.
4. Mortar shrinkage
The thermal insulation mortar will shrink to a certain extent during the hardening process. If the shrinkage of the mortar is too large and it is not maintained in time, cracks are likely to form on the surface. Especially in thick mortar or large-area construction, the shrinkage deformation is large, which is easy to cause cracks. The cause of shrinkage may be related to factors such as improper mortar ratio, low humidity in the construction environment, and insufficient maintenance.
5. Uneven or improperly treated base surface
The uneven base surface or impurities attached to the surface affect the adhesion between the thermal insulation mortar and the base surface, which is easy to cause cracks. If the base surface is not properly treated before construction (such as cleaning, leveling, etc.), the adhesion between the mortar and the base surface is poor, and cracks are likely to occur during the drying process.
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6. Improper construction technology
Construction technology is one of the key factors in the quality of thermal insulation mortar. Improper construction methods such as uneven application, different thicknesses, too fast or too slow construction speed will cause uneven shrinkage of the mortar layer and form cracks. In addition, uneven mixing or excessive mixing of the mortar will also affect the performance of the mortar and cause cracks.
7. External force
After the construction of the thermal insulation mortar, the external force (such as temperature changes, humidity changes, building settlement, etc.) may also cause cracks. Especially during the settlement of the building, the mortar layer is stretched or compressed, which is prone to cracks.
8. Premature demoulding or improper maintenance
After the construction is completed, the thermal insulation mortar needs to be adequately maintained before demoulding to ensure that the mortar can be fully hydrated and hardened. If sufficient humidity or curing time is not provided during the hardening process, the mortar will cause the surface to dry and crack due to excessive water loss. In addition, premature demoulding or unsuitable external conditions may also lead to the formation of cracks on the mortar surface.
9. Quality problems of the insulation material itself
If the insulation materials (such as polystyrene boards, extruded boards, etc.) used in the insulation mortar are of unqualified or uneven quality, the structure of the mortar layer may be unstable and cracks may occur. For example, the poor adhesion between the insulation board and the mortar, or the presence of bubbles and cracks inside the insulation material, will affect the overall stability of the mortar.
10. Chemical reaction
In some cases, the additives used in the insulation mortar react adversely with other materials, causing changes in the physical properties of the mortar, which may in turn cause cracks. For example, certain chemical components react with cement to produce expansion or contraction products, which affect the hardness and stability of the mortar and cause cracks.
The generation of cracks in the insulation mortar is the result of the combined action of multiple factors, including raw material ratio, construction process, environmental conditions, base surface treatment, etc. In order to effectively prevent the generation of cracks, it is necessary to strictly control each link during the construction process, select qualified raw materials, ensure appropriate construction technology, and reasonably control the construction environment and maintenance conditions. Through these measures, the occurrence of cracks can be significantly reduced and the quality and service life of the thermal insulation mortar can be improved.
Post time: Jun-12-2025