How construction mortar is classified?

Dry-mix mortar production equipment manufacturers explain how construction mortar is classified? Construction 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, special mortar. Special mortars include waterproof mortars, acid-resistant mortars, adiabatic mortars, sound-absorbing mortars, etc. Construction mortars are classified according to the cementitious material: 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.

The strength level of mortar is influenced by the composition of the mortar itself, the matching ratio, the construction process, the construction and hardening conditions, but also the water absorption rate of the masonry material. The strength grade of mortar is also affected by the high content of mud and other impurities in the sand.
The mortar strength grade is determined by the compressive strength value of a cube test block with a side length of 7.07 cm, cured to 28d under standard conditions [at a temperature of (20±2)°C and relative humidity of 90% or more]. The mortar strength grade is generally determined according to the drawings and design requirements. For example, if the drawings indicate M7.5 mortar for masonry, you will have to use M7.5 mortar. Generally the design drawings indicate M5, M7.5, M10, M20, the cement and sand from the construction site need to be sent to the laboratory to make the ratio, make a set of 70.7X70.7X70.7 test blocks and carry out a compressive test after 28 days of standard maintenance to see if the test blocks can reach the design strength. The masonry mortar is tested according to the compressive strength.

Masonry mortar is divided into six strength classes according to compressive strength, such as M20, M15, M10, M7.5, M5.0 and M2.5. In general, multi-storey building walls with M2.5-M15 masonry mortar; masonry masonry foundation, inspection wells, rainwater wells, etc. commonly used M5 mortar; industrial plants, substations, basements and other masonry with M2.5-M10 masonry mortar; two-storey buildings commonly used below M2.5 mortar; simple cottages, temporary buildings can choose lime mortar; general highway construction drains use Masonry mortar of strength class M7.5.

Construction mortar is composed of inorganic cementitious materials, fine aggregates and water, sometimes mixed with certain adulterants. Construction mortar is commonly used for masonry (e.g. brick, stone, block) structures, plastering of internal and external surfaces of buildings (e.g. walls, floors, roofs), hooking of large wall panels, masonry walls, and bonding of decorative materials. The mortar that bonds bricks, stones and blocks into masonry is called masonry mortar. Masonry mortar is made up of cement, other cementitious materials (e.g. lime paste, clay paste, etc.), fine aggregates and water. The cement can be selected according to the design requirements, the masonry part and the environmental conditions in which it is located. Choose a low to medium strength cement that will meet the requirements. Cement mortar should not have a strength grade greater than 32.5; cement mix mortar should not have a strength grade greater than 42.5.

When lime is ripened into lime paste, it should be filtered through a net with an aperture of not more than 3mm x 3mm and the ripening time should not be less than 7 days; the ripening time for finely ground lime powder should not be less than 2 days. Measures should be taken to prevent drying, freezing and pollution of the lime paste stored in the settling pond. The use of dehydrated and hardened lime paste is strictly forbidden. The consistency of the lime plaster used should be controlled to around 120mm. The sand used for masonry mortar should be medium sand, of which coarse sand should be used for rough stone masonry and its mud content should not exceed 5%; for cement mix mortar with strength class M2.5, the mud content of the sand should not exceed 10%. For mortar mixing, clean water free from harmful impurities should be used for mortar mixing.