Possible problems with dry-mix mortar

1. Why does dry-mixed mortar clump and form a mass on the construction site, and the quality declines?

1.1 Cause analysis:
1.1.1 The moisture content of the raw material sand of the mortar manufacturer does not meet the sand drying requirements. The mortar mixing time is too short. The mixing is uneven.
1.1.2 The mortar manufacturer does not use raw materials in a standardized manner.
1.1.3 The construction company failed to clean the dry-mixed mortar silo and mixer in time according to the construction requirements of premixed dry-mixed mortar.
1.2 Preventive measures:
1.2.1 Mortar manufacturers should formulate a strict quality management system. Formulate quality policies and quality objectives to establish an organizational structure. Strengthen production process control and raw material testing.
1.2.2 Mortar manufacturers should provide good on-site services. Introduce product features and provide product manuals. Ensure project quality.
1.2.3 Construction companies should improve mortar project quality responsibility measures. Special personnel are responsible for maintenance and cleaning of dry-mixed mortar silos.

2. Why do dry-mixed mortars have unqualified test blocks, fluctuate in strength, have large deviations, and fail to meet strength judgments. But other construction sites, at the same time, at the same location, and with the same mix ratio, all qualified with small deviations?

2.1 Cause analysis: 4.1.1 The construction unit adopted unqualified test touches, and the test piece error itself was too large. Some test molds had diagonal errors of >3mm, resulting in large test piece errors.
2.1.2 The test piece was made roughly and did not meet the relevant specifications, and standard maintenance was not performed.
2.1.3 The test piece itself was unqualified, the force-bearing area did not meet the requirements, and local compression occurred, and the strength was low.
2.2 Preventive measures:
2.2.1 It is recommended that the construction unit’s experimental personnel receive technical training and learn the standards and specifications of relevant experiments.
2.2.2 Replace unqualified test molds, and strengthen monitoring of the used test molds. If they do not meet the requirements, they will not be used.

3. Why do bubbles appear soon after the dry-mixed mortar is applied?

3.1 Cause analysis:
3.1.1 The mortar admixture or water-retaining thickening material is not compatible with cement, resulting in bubbles in the reaction.
3.1.2 The fineness modulus of the raw material sand of the mortar is too low or the particle grading is not good, resulting in too high porosity and bubbles.
3.2 Preventive measures:
3.2.1 Strengthen the compatibility test of raw materials, especially admixtures and water-retaining thickening materials with cement. Only qualified can it be used for production.
3.2.2 Reasonably adjust the particle grading and various indicators of the sand. Ensure that the mortar is qualified before leaving the factory.
The above are the possible problems of dry-mix mortar summarized by Landcel.