1. What materials are building mortar made of? What are the common uses of building mortar?

Answer: Building mortar is composed of inorganic cementitious materials, fine aggregates and water, and sometimes certain admixtures are added. Building mortar is often used for masonry (such as bricks, stones, blocks) structures. Plastering of the internal and external surfaces of buildings (such as walls, floors, ceilings). Grouting of large wall panels, masonry walls, and bonding of decorative materials.

2. How is building mortar classified?

Answer: Building mortar is classified according to its use: it can be divided into masonry mortar and plastering mortar.
Plastering mortar includes ordinary plastering mortar, decorative plastering mortar, and special mortar.
Special mortars include waterproof mortar, acid-resistant mortar, insulation mortar, sound-absorbing mortar, etc.
Building mortar is classified according to cementitious materials: it can be divided into cement mortar, lime mortar, and mixed mortar.
Mixed mortar can be divided into: cement lime mortar, cement clay mortar, lime clay mortar, lime fly ash mortar, etc.

3. What is masonry mortar and what materials does it consist of?

Answer: The mortar that bonds bricks, stones, blocks, etc. into masonry is called masonry mortar.
The material composition of masonry mortar: cement, other cementing materials (such as lime paste, clay paste, etc.), fine aggregate and water.

4. What should be paid attention to when choosing masonry mortar?

Answer: Cement can be selected according to design requirements, masonry locations and environmental conditions. Choosing medium and low strength cement can meet the requirements. The strength grade of cement used in cement mortar should not be greater than 32.5. The strength grade of cement used in cement mixed mortar should not be greater than 42.5.

When quicklime is matured into lime paste, it should be filtered with a mesh with an aperture of no more than 3mm×3mm, and the maturation time should not be less than 7 days.

The maturation time of ground quicklime powder should not be less than 2 days. Measures should be taken to prevent the lime paste stored in the sedimentation tank from drying, freezing and contamination. It is strictly forbidden to use dehydrated and hardened lime paste. The consistency of the lime paste used should be controlled at about 120mm.

Medium sand should be used for masonry mortar. Among them, coarse sand should be used for rough stone masonry. Its mud content should not exceed 5%. Cement mixed mortar with strength grade M2.5. The mud content of sand should not exceed 10%. Clean water without harmful impurities should be used to mix mortar.

5. What properties should the mixed mortar have?

Answer: The mixed mortar should have the following properties: meet the workability requirements. Meet the design type and strength grade requirements. Have sufficient bonding force.

6. What are the properties of masonry mortar? What are the contents of mortar workability?

Answer: The properties of masonry mortar include mortar workability, mortar strength and mortar bonding force. Mortar workability includes fluidity and water retention.

7. How is the fluidity of mortar expressed, and what are the factors that affect it?

Answer: The fluidity of mortar is also called consistency, which refers to the performance of flowing under the action of dead weight or external force. It is expressed by “sinking degree”. The larger the sinking degree, the greater the fluidity of the mortar. However, if the fluidity is too large, the strength will decrease after hardening. If the fluidity is too small, it will be inconvenient for construction operations.

The fluidity of mortar is related to factors such as the type of masonry material, construction conditions and climatic conditions. For porous water-absorbing masonry materials and dry and hot weather. The mortar is required to have greater fluidity. On the contrary, for dense non-absorbent materials and wet and cold weather. The fluidity is required to be smaller.