Cement: powdery hydraulic inorganic cementitious material . After adding water and stirring, it becomes a slurry , which can harden in the air or in water, and can firmly bond sand, stone and other materials together.
The mixture of early lime and pozzolan is very similar to modern lime pozzolan cement [1] . The concrete made by cementing gravel with it will not only have higher strength after hardening , but also resist the erosion of fresh water or salt water. For a long time, it has been widely used in civil engineering , water conservancy , national defense and other projects as an important cementing material .
Cement is divided into:
(1) General Cement: General civil construction cement works commonly used. General-purpose cement mainly refers to the six major types of cement specified in GB175-2007, namely Portland cement , ordinary Portland cement, slag Portland cement , pozzolanic Portland cement, fly ash Portland cement and composite Portland cement .
(2) Special cement: cement with special properties or purposes, such as G-grade oil well cement, fast hardening portland cement, road portland cement , aluminate cement , sulphoaluminate cement, etc.
Cement is classified according to the names of its main hydraulic substances:
(1) Portland cement , which is commonly known as Portland cement abroad;
(2) Aluminate cement ;
(3) Sulphoaluminate cement ;
(4) Ferro-aluminate cement ;
(5) Fluoroaluminate cement ;
(6) Phosphate cement;
(7) Cement with pozzolan or latent hydraulic materials and other active materials as the main components.
Cement is divided into main technical characteristics:
(1) Quick hardening (hydraulic hardening): divided into two types: quick hardening and super hard hardening;
(2) Heat of hydration : divided into two types: medium heat and low heat;
(3) Sulfate resistance: It is divided into two categories: medium sulfate corrosion resistance and high sulfate corrosion resistance;
(4) Expansibility: Divided into two categories : expansion and self-stress;
(5) High temperature resistance: The high temperature resistance of aluminate cement is classified according to the alumina content in the cement.
The principle of cement naming :
Cement is named according to different categories based on the main hydraulic minerals, mixed materials, uses and main characteristics of the cement, and strives to be concise and accurate. If the name is too long, abbreviations are allowed.
General-purpose cement is named after the name of the main hydraulic mineral of cement, followed by the name of the mixed material or other appropriate names.
Special cement is named after its special purpose and can be named with different models.
The characteristic cement is named after the main hydraulic minerals of the cement and the main characteristics of the cement, and it can be named by different models or mixed materials.
Cement with pozzolanic or potentially hydraulic materials and other active materials as the main component is named after the name of the main component with the name of the active material, or it can be named after the characteristic, such as gypsum slag cement , lime pozzolan cement Wait.
Definition of cement type
(1) Cement: It is a powdery hydraulic cementing material that can be mixed with water to form a plastic slurry, which can cement sand, stone and other materials that can harden in the air and harden in water .
(2) Portland cement: a hydraulic cementing material made from Portland cement clinker , 0% to 5% limestone or granulated blast furnace slag , and an appropriate amount of gypsum, called Portland cement, divided into PI And P.II, which is commonly known as Portland Cement abroad.
(3) Ordinary Portland cement: a hydraulic cementitious material made of Portland cement clinker, 6%-20% mixed materials, and an appropriate amount of gypsum, called ordinary Portland cement (or ordinary cement for short) , Code: PO.
(4) Portland slag cement: a hydraulic cementing material made from Portland cement clinker, 20% to 70% granulated blast furnace slag and an appropriate amount of gypsum, called slag Portland cement, code name: PS.
(5) Pozzolanic Portland cement: a hydraulic cementing material made of Portland cement clinker, 20%-40% pozzolanic mixed materials and an appropriate amount of grinded gypsum, called pozzolanic Portland cement, Code: PP.
(6) Fly ash Portland cement : a hydraulic cementing material made from Portland cement clinker, 20% to 40% fly ash and an appropriate amount of gypsum, called fly ash Portland cement , Code: PF.
(7) Composite Portland cement: a hydraulic cementitious material made of Portland cement clinker, 20%-50% of two or more specified mixed materials and an appropriate amount of finely ground gypsum, called composite silica Salt cement (composite cement for short), code-named PC.
(8) Moderate heat Portland cement : a hydraulic cementing material with moderate heat of hydration made of Portland cement clinker of appropriate composition and ground with appropriate amount of gypsum.
(9) Low-heat slag Portland cement : a hydraulic cementing material with low heat of hydration made from Portland cement clinker of appropriate composition and ground with appropriate amount of gypsum.
(10) Quick-hardening Portland cement : Portland cement clinker is added with appropriate amount of gypsum, and ground to produce cement with high early strength and 3 days compressive strength .
(11) Sulfate-resistant Portland Cement : Cement made from Portland cement clinker and finely ground gypsum with good sulfate corrosion resistance.
(12) White Portland cement : a low content of iron oxide added amount of Portland cement plaster, made of ground white cement .
(13) Road portland cement: a hydraulic cementitious material made from road portland cement clinker, 0% to 10% active mixed materials and an appropriate amount of grinded gypsum, called road portland cement, (abbreviated as Road cement ).
(14) Masonry cement: It is made of active mixed materials, adding appropriate amount of Portland cement clinker and gypsum, and ground to make low-grade cement mainly used for masonry mortar .
(15) Oil well cement : Cement made of Portland cement clinker with appropriate mineral composition, appropriate amount of gypsum and mixed materials, etc., which is suitable for oil and gas well cementing engineering under certain well temperature conditions .
(16) Gypsum slag cement: The granulated blast furnace slag is the main component material, and the appropriate amount of gypsum, Portland cement clinker or lime is ground to make cement.
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