After the construction of dry-mixed mortar, the plastered surface may have problems such as sand loss, surface powder and peeling, and rough plastered surface. After the dry-mixed mortar hardens, there will be hollowing, shedding, and penetration quality problems?
What are the reasons for these problems? What is the solution? Landcel to tell you.
1. Why does the dry-mixed mortar appear to be sand-dropped on the surface?
1.1 Cause analysis: mainly due to mortar
The fineness modulus of the sand used as raw material is too low, the mud content exceeds the standard, and the proportion of cementitious materials is small. As a result, part of the sand floats out of the surface and causes sanding.
1.2 Preventive measures:
1.2.1 Strictly control sand fineness modulus, particle gradation, mud content and other indicators.
1.2.2 Increase the gelling material and adjust the formula in time.
2. Why does the dry-mixed mortar appear powder and peeling on the surface?
2.1 Reason analysis:
Mainly because the bulk density of the raw material admixture used in the mortar is too low, and the proportion of the admixture is too large. Due to calendering, part of the powder floats up and gathers on the surface, so that the surface strength is low and the powder falls off.
2.2 Preventive measures:
Understand the performance and addition ratio of various admixtures, pay attention to trial preparation and formula adjustment.
3. Why is the dry-mixed mortar easy to fall off and not stick to the surface?
3.1 Reason analysis:
3.1.1 Mortar has poor workability and low cohesive force.
3.1.2 The construction party plastered too thickly at one time, and the plastering time interval was too short.
3.1.3 Improper handling of the substrate interface.
3.2 Preventive measures:
3.2.1 Adjust the formula according to different raw materials and substrates to increase the adhesion.
3.2.2 It is recommended to plaster in layers during construction, the total thickness should not exceed 20mm, and pay attention to the time of each process.
3.2.3 Do a good job of interface treatment, especially some new wall materials, or use special matching mortar.
4. Why does the dry-mixed mortar have a rough plaster surface and uneven finish after plastering without pulp?
4.1 Cause analysis:
There are too many large particles of lightweight aggregate (sand) in the ready-mixed dry-mixed mortar raw material, and the fineness modulus is too high. The resulting slurry becomes less and cannot be lightened.
4.2 Preventive measures:
Adjust the mortar light aggregate (sand) particle gradation and increase the powder appropriately.
5. Why does the dry-mixed mortar have hollowing, shedding, and penetration quality problems after hardening?
5.1 Reason analysis:
5.1.1 Mortar quality problems caused by lax quality management of production enterprises and inadequate production control.
5.1.2 Use problems caused by poor construction quality of construction enterprises.
5.1.3 It is caused by the mismatch between the interface agent and adhesive used in the wall interface treatment and the dry-mixed mortar.
5.1.4 Temperature changes cause expansion or contraction of building materials.
5.1.5 The wall itself is cracked.
5.2 Preventive measures:
5.2.1 The production unit should improve the measures and responsibilities for the quality management of ready-mixed dry-mixed mortar.
5.2.2 Construction enterprises should improve the construction measures and responsibilities of ready-mixed dry-mixed mortar engineering quality.