What is the label of Portland cement?

l) Technical performance indicators of Portland cement.

Fineness: The fineness of Portland cement is not less than 3d0 square meters kg of specific surface area.

Insoluble matter: The content of insoluble matter in Portland cement is not greater than.

MGO content: The MGO content in Portland cement is not greater than.

SO3 content: SOs in Portland cement. The content is not greater than.

Loss on ignition: The content of loss on ignition in Portland cement is not greater than.

Label: The label of Portland cement and the strength value of each age are shown in Table 3 2.

Table 3 2 Strength values of Portland cement at different ages.

Labeling Compressive Strength, MPa Flexural Strength, MPa

3 days 28 days 3 days 28 days.

425r 22．0 42．5 4．0 6．5

525r 27．0 52．5 5．0 7．0

625r 32．0 62．5 5．5 8．0

Note: R is a strong type in the morning.

2) Technical performance indicators of ordinary Portland cement.

Fineness: The fineness of ordinary Portland cement is indicated, that is, the sieve residue of the square hole is not more than 10.

Insoluble matter: The content of insoluble matter in ordinary Portland cement is not greater than.

MGO content: ordinary Portland cement MGO. The content is not greater than.

SO content: ordinary Portland cement SO. The content is not more than 3 5 .

Loss on ignition: The loss on ignition in ordinary Portland cement is not greater than 3 5

Label: The label of ordinary Portland cement and the strength value of each age are shown in Table 3 3.

Table 3 3 Strength values of ordinary Portland cement at different ages.

Labeling Compressive Strength, MPa Flexural Strength, MPa

3 days 28 days 3 days 28 days.

425r 21．0 42．5 6．5

525r 26．0 52．5 5．0 7．0

625r 31．0 62．5 5．0 8．0

3) Technical performance indicators of slag Portland cement, fly ash Portland cement, and porosyl silicate sludge.

Fineness. The fineness of slag cement, pozzolane cement and fly ash cement is expressed by the sieve allowance, that is, the 0 080mm square hole sieve allowance shall not exceed.

Insoluble matter: slag cement, pozzolane cement and fly ash cement do not specify the insoluble matter content.

MGO content: the MGO content of slag cement, pozzolana cement and fly ash cement is not more than 5 0. A loss on ignition: slag cement in the loss of ignition is not more than 50, the other two kinds of cement do not require the loss on ignition.

SO3 content: SOs in pozzolana cement and fly ash cement. The content is not more than 3 5, so in slag cement. The content is not more than 4 0 ".

Labeling: The labeling of slag cement, pozzolana cement and fly ash cement and the strength values of each age are shown in Table 3 4. Table 3-4 Intensity values at different ages.

Labeling Compressive Strength, MPa Flexural Strength, MPa

3 days 7 days 28 days 3 days 7 days 28 days.

425r525r

625r

After the test block is made, the compressive strength is the number value.

Ordinary Portland cementThe code name is:

Ordinary Portland cement is a hydraulic cementitious material made of Portland trembling cement clinker, 5%-20% mixed materials and an appropriate amount of gypsum grinding. It has the characteristics of high strength, high heat of hydration, good frost resistance, dry shrinkage, good wear resistance, good carbonization resistance, poor corrosion resistance, and no high temperature resistance.

GB175-2007 provides:

The hydraulic cementitious material made of Portland cement clinker, 5%-20% mixed materials and an appropriate amount of gypsum grinding is called ordinary Portland cement, referred to as ordinary cement.

Basic properties: 1. Fast setting and hardening, high early strength and later strength, suitable for concrete with early strength requirements, winter construction concrete, and high-strength concrete for important structures above ground and underground.

and prestressed concrete works.

2. It has good frost resistance, and is suitable for concrete rolling process that is subjected to repeated freeze-thaw cycles within the range of water level rise and fall in severe cold areas.

3. The heat of hydration is large, so it is not suitable for large-volume concrete.

engineering, but can be used for construction in the low temperature season or winter.

4. Poor corrosion resistance, not suitable for frequent use with flowing fresh water or sulfate.

and other corrosive media contact projects, and should not be used for projects that are often in contact with corrosive media such as seawater and mineral water.

5. Poor heat resistance, not suitable for concrete projects with heat resistance requirements.

6. Good carbonization resistance, suitable for environments with high CO2 concentration in the air, such as foundry workshops, etc.

7. Dry shrinkage, which can be used for concrete projects in dry environments.

8. Good wear resistance, can be used for pavement and ground engineering.

The unmixed material is Portland cement I, the code is P i, and the mixed material mixed with no more than 5% of the defective quality of the cement is Portland cement, the code is P.

Where to calcium silicate.

Mainly Portland cement clinker, less than 5% limestone or granulated blast furnace slag, and an appropriate amount of gypsum grinding to make a hydraulic cementitious material, collectively known as Portland cement, internationally collectively known as Portland cement.

Sign. The cement packaging bag should be clearly marked: the implementation standard.

Cement variety, code, strength grade, producer name, and production license are false.

Marking (QS) and number, factory number, packing date, net content.

The cement name and strength grade should be printed on both sides of the packaging bag in different colors according to the variety of cement, Portland cement and ordinary Portland cement.

red, slag Portland cement green; Pozzolana Portland Mud, Fly Ash Portland Cement and Composite Portland Cement are available in black or blue.

po。

The strength grade of ordinary Portland cement is divided into5r
.5R four grades; The strength grades of slag silicate cement, pozzolana Portland cement, fly ash Portland cement, and composite Portland cement are divided into

5r
.5r
.5R six levels.

Before 1999, cement was divided into grades according to the label, and the number sequence and the current strength grade sequence did not correspond to the strict and difficult grid, but in practice, the current strength grade was often multiplied by the product of 10 and the value after 100 to find the correspondence.

Portland cement precautions.

The hardening speed of Portland cement is fast, the strength is high, the heat of hydration is large, and the high temperature resistance is low, so it can be used in the structure that requires higher strength when in use, and can also be used in the engineering of winter construction, but it is not suitable for being used in large-volume concrete engineering and the project with heat resistance requirements.

Portland cement should be stacked separately according to the label and factory date when stored, and the stacking height of bagged cement is generally not more than 10 bags. The storage date of cement should not be too long, generally the source of non-lead is more than three months from the date of manufacture, otherwise the strength grade should be re-determined, and used according to the measured strength. Attention should also be paid to moisture protection during storage.

Ordinary Portland cement is a hydraulic cementitious material made of Portland cement clinker, 5%-20% mixed material and an appropriate amount of gypsum grinding. It has the characteristics of high strength, high heat of hydration, good frost resistance, dry shrinkage, good resistance to selling and grinding, good carbonization resistance, poor corrosion resistance, and no high temperature resistance.

GB175-2007 stipulates that the hydraulic cementitious material made of Portland cement clinker, 5%-20% mixed materials and an appropriate amount of gypsum grinding is called ordinary Portland cement, referred to as ordinary cement.

Basic performance. a. Fast coagulation and hardening, high early strength and later strength, suitable for concrete with early strength requirements, winter construction concrete, high-strength concrete and prestressed concrete projects of important structures above ground and underground.

b. Good frost resistance, suitable for concrete projects subject to repeated freeze-thaw cycles within the range of water level rise and fall in severe cold areas.

c. The heat of hydration is large, and it is not suitable for large-volume concrete projects, but it can be used for low-temperature season or winter construction.

d. Poor corrosion resistance, not suitable for projects that are often in contact with corrosive media such as flowing fresh water or sulfate, nor should it be used for projects that are often in contact with corrosive media such as seawater and mineral water.

e. Poor heat resistance, not suitable for concrete projects with heat resistance requirements.

f. Good carbonization resistance, suitable for environments with high CO2 concentration in the air, such as foundry workshops, etc.

g. Dry shrinkage, which can be used for concrete engineering in a dry environment.

h. Good wear resistance, can be used for pavement and ground engineering.

GB175-2020 General Portland Cement Standard, the full name of the standard is GB175-2020 "General Portland Cement", which is a mandatory national standard for Cong Songsui. The standard stipulates the definition and classification, composition and material, strength grade, technical requirements, test methods, inspection rules and packaging, marking, transportation and storage of general Portland cement. This standard applies to Portland cement general-purpose.

All clinker of Portland permeable cement based on calcium silicate, limestone or granulated blast furnace slag below 5%, and a suitable amount of gypsum grinding are collectively referred to as Portland cement, and are collectively referred to as Portland cement in the world.

Portland cement introduced

The main mineral components of Portland cement are: tricalcium silicate, dicalcium silicate, tricalcium syllabus, and tetracalcium iron aluminate. Tricalcium silicate determines the strength of Portland cement in four weeks; Dicalcium silicate only exerts its strength effect after four weeks, and it reaches the strength of tricalcium silicate for about four weeks in about a year.

Portland cement has the performance characteristics of short setting time, fast hardening, early strength, high strength, frost resistance, wear resistance, heat resistance, concentrated hydration and heat release, and large heat of hydration. Portland cement is used for the preparation of high-strength concrete, pre-tensioned prestressed products, roads, low-temperature construction projects and general heating (250) projects.

The above content reference: Encyclopedia - General Portland cement.