Some problems about mortar and concrete ~ ~

GB6566 Radionuclide Limit of Building Materials

JGJ98 Specification for Mix Design of Masonry Mortar

JGJ52 Quality Standard and Inspection Method of Sand for Ordinary Concrete

GBl345 Cement fineness test method-Sieve analysis method

GBl596 is used for fly ash in cement and concrete.

JC 474- 1999 Waterproofing agent for mortar and concrete

JGJ63 Water Standard for Concrete Mixing

GB9776-88 Building gypsum

GB 9774 cement packaging bag

GB 50209 Code for Acceptance of Construction Quality of Building Ground Engineering

GB 502 10 Code for Acceptance of Construction Quality of Architectural Decoration Engineering

GB 50203 Code for Acceptance of Masonry Construction Quality

JGJ70 Test Method for Basic Properties of Building Mortar

Gb/t503 15 Technical Standard for Site Inspection of Masonry Engineering.

Technical specification for testing compressive strength of masonry mortar by penetration method (JGJ/T 136)

GBJl29 Standard for Test Methods of Basic Mechanical Properties of Masonry

GB/T 19 1 graphic signs for packaging, storage and transportation.

3 Terms and definitions

3. 1 ready-mixed mortar

Ready-mixed mortar refers to the mortar produced by professional manufacturers and used in general industrial and civil construction projects, including dry mixed mortar and wet mixed mortar.

3.2 Dry mixed mortar

Dry-mixed mortar material' refers to the granular or powdery mixture of fine aggregate produced by professional manufacturers after drying and screening, mixed with inorganic binder, mineral admixture and additives in a certain proportion. At the construction site, add water and stir according to the instructions to become mortar mixture. The packaging forms of products can be divided into bulk or bags. Dry-mixed mortar includes cement mortar and gypsum mortar.

3.3 Wet mixed mortar

Referred to as wet-mixed mortar, it refers to a mortar mixture made of cement, sand, water-retaining thickening materials, water, fly ash or other mineral admixtures and additives in a certain proportion, which is transported to the place of use by a mixer for proper storage and used up within a specified time, including masonry, plastering and ground mortar.

3.4 Ordinary ready-mixed mortar

Ordinary ready-mixed mortar is a general term for ready-mixed masonry mortar, ready-mixed plastering mortar and ready-mixed ground mortar, which can be dry-mixed mortar or wet-mixed mortar. Ready-mixed mortar in this regulation refers to ordinary ready-mixed mortar.

3.5 Special ready-mixed mortar

Special ready-mixed mortar refers to ready-mixed mortar with special functions such as impermeability, crack resistance, high adhesion and decoration, including ready-mixed waterproof mortar, ready-mixed wear-resistant mortar, ready-mixed self-leveling mortar and ready-mixed thermal insulation mortar.

3.6 Water-retaining thickening material Water-retaining plastic admixture

Water-retaining thickening material refers to the non-lime powder material used in ready-mixed mortar to improve the workability of mortar.

3.7 storage time

For wet-mixed mortar, the storage time refers to the time when the wet-mixed mortar is stored and kept in a certain way after being transported to the construction site, which can ensure the performance of the mortar. For dry-mixed mortar, the storage time refers to the time from bagging or canning of dry-mixed mortar to mixing with water, and the storage time of dry-mixed mortar should be shorter than its validity period.

4.2. 1 Symbols used to identify ready-mixed mortar shall be used according to the following provisions according to their classification and different materials used:

A)DM- dry mixed mortar

Dry mixed masonry mortar

DPM- dry mixed plastering mortar

DSM- Dry-mixed ground mortar

WM- wet mixed mortar

WMM- wet mixed masonry mortar

Wet mixed plastering mortar

WSM- wet mixed ground mortar

B) Cement varieties are indicated by their codes;

C) gypsum is represented by g;

D) Consistency and strength grade are expressed by numbers.

4.2.2 Marking of dry-mixed mortar

The symbols of dry-mixed masonry mortar, dry-mixed plastering mortar and dry-mixed ground mortar can be expressed by the combination of their types, strength grades, consistency and types of cementitious materials.

4.2.3 Marking of wet mixed mortar

The symbols of wet-mixed masonry mortar, wet-mixed plastering mortar and wet-mixed ground mortar can be expressed by their categories, strength grades, consistency and setting time.

5 technical requirements of ready-mixed mortar

5. 1 General provisions

5. 1. 1 The technical performance indexes of raw materials, mortar mixture and hardened mortar body of ready-mixed mortar shall meet the design requirements, relevant national standards and relevant provisions of this specification.

5. 1.2 The ready-mixed mortar is graded according to the compressive strength of 70.7mm×70.7mm×70.7mlB cube and the 28-day standard curing specimen.

5. 1.3 Radionuclide specific activity of ready-mixed mortar shall comply with the provisions of GB 6566 standard.

5. 1.4 the corresponding relationship between ready-mixed mortar and traditional mortar is shown in table 5. 1.4, and various ready-mixed mortars can be selected according to their strength requirements.

Table 5. 1.4 Correspondence between ready-mixed mortar and traditional mortar

Types of ready-mixed mortar Traditional mortar

Masonry mortar DMM5.0, WMM5.0, DMM7.5, WMM7.5

DMMl0, WMMl0 M5.0 mixed mortar and M5.0 cement mortar.

M7.5 mixed mortar, M7.5 cement mortar.

M 10 mixed mortar and M 10 cement mortar.

Plastering mortar DPM5.0, WPM5.0

DPMl0、WPMl0

DPMl5 and wpml 5 1: 1:6 mixed mortar

1: 1:4 mixed mortar

1: 3 cement mortar

Ground mortar DSM20, WSM 20 1: 2 cement mortar

5.2 Quality standard of dry-mixed mortar

5.2. 1 The brands of dry-mixed masonry mortar are DMM30, DMM25, DMM20, DMMl5, DMMl0, DMM7.5, DMM5.0, etc. The performance requirements are listed in Table 5.2. 1.

Table 5.2. 1 Performance of Dry-mixed Masonry Mortar

intensity

Hierarchical consistency

(mm) water retention rate (%) 28d compressive strength (MPa) setting time

(h) 28d shrinkage (%) DMM 30 DMM 25 DMM 20 DMM L5 DMML 0 DMM 7.5 DMM 5.0 ≤ 90 88 ≥ 30.0.

≥25.0

≥20.0

≥ 15.0

≥ 10.0

≥7.5

≥5.0 ≤ 10

≤0.5

5.2.2 The grades of dry-mixed plastering mortar are DPM20, DPM 15, DPM 10, DPM7.5, DPM5.0, etc. , and its performance requirements are listed in table 5.2.2.

Table 5.2.2 Performance of Dry-mixed Plastering Mortar

Strength grade consistency (mm) water retention rate (%) 28d

Compressive strength (Mpa) setting strength (MPa) bonding time (h) 28d shrinkage (%) impermeability DPM20

DPMl5

DPMl0

DPM7.5

DPM5.0 ≤ 1 10 ≥92 ≥20.0

≥ 15.0

≥ 10.0

≥7.5

≥5.0 ≤ 10 ≥0.3 ≤0.5 meets the design requirements.

5.2.3 The grades of dry-mixed ground mortar are DSM25, DSM20, DSMl5, etc. Table 5.2.3 lists the performance requirements.

Table 5.2.3 Basic Performance of Thousand-mixed Ground Mortar

Consistency of strength grade

(mm) water retention rate (%) 28d compressive strength (MPa) setting time

(h) 28d shrinkage (%) DSM25

DSM20

DSMl5 ≤50 ≥90 ≥25.0

≥20.0

≥ 15.0 ≤ 10 ≤0.5

5.2.4 The uniformity requirements of bulk dry-mixed mortar shall comply with the provisions in Table 5.2.4.

Table 5.2.4 Uniformity Requirements of Bulk Mixed Mortar

The absolute error between the passing rate of 80L 1m square hole sieve and the average value is% or less than 3.

The relative error between the 28d compressive strength and the true value is% ≤20.

See appendix c for uniformity test method.

5.3 Quality standard of wet mixed mortar

5.3. 1 wet-mixed masonry mortar has 7 grades: WMM30, WMM 125, WMM20, MM 15, WMM 10, WMM7.5 and WMM5.0. See Table 5.3./kl.

Table 5.3. 1 Performance of wet-mixed masonry mortar

Consistency of strength grade

(mm) water retention (%) setting time

(h) 28d compressive strength (MPa) 28d shrinkage (%) WMM 3050 ~ 90 ≥ 858, 12, 24 ≥30.0.

≥25.0

≥20.0

≥ 15.0

≥ 10.0

≥7.5

≥5.0 ≤0.5

5.3.2 Wet-mixed plastering mortar has five strength grades: WPM20, WPMl5, WPMl0, WPM7.5 and WPM5.0, and its performance requirements are shown in Table 5.3.2.

Table 5.3.2 Performance of Wet-mixed Plastering Mortar

intensity

Graded consistency (mm) Water retention rate (%) Setting time

(h) 28d adhesive strength (MPa) 28d compressive strength (MPa) 28d shrinkage (%) Impermeability is sprayed by hand machine.

WPM20

WPMl5

WPMl0

wPM7.5

wpm 5.0 60 ~ 90 80 ~ 1 10≥90 8、 12、24 ≥0.3 ≥20.0

≥ 15.0

≥ 10.0

≥7.5

≥5.0 ≤0.5 meet the design requirements.

5.3.3 Wet-mixed ground mortar has three strength grades: wSM25, WSM20 and WSMl5, and its performance requirements are shown in Table 5.3.3.

Table 5.3.3 Performance of Wet-mixed Ground Mortar

intensity

Hierarchical consistency

(mm) water retention (%) setting time

(h) 28d compressive strength (MPa) 28d shrinkage (%) WSM25

WSM20

WSMl5 30—50 ≥85 4、8 ≥25.0

≥20.0

≥ 15.0 0.5

5.3.4 The allowable deviation of consistency of wet-mixed mortar shall comply with the provisions in Table 5.3.4. The difference of mortar consistency measured at the delivery place shall not exceed the allowable deviation in the table, and the consistency loss shall not be greater than 35% of the measured consistency of delivery within the specified time.

Table 5.3.4 Allowable deviation range of consistency

The allowable deviation (mm) of the specified consistency is 30 ~ 49-5.

+ 10

50~69 10

70~ 100 15

1 10 +5

- 10

5.3.5 The setting time of wet-mixed mortar shall be determined by both parties through consultation, but generally it shall not exceed 24 hours. It is stipulated that the consistency loss of wet-mixed mortar shall not be greater than 35% within the storage time specified in the contract, that is, the operability of wet-mixed mortar shall be ensured within the storage time specified in the contract. 6 production quality control