Add appropriate amount of gypsum to the Portland cement clinker, and grind the cement into four grades of 425, 525, 625, and 725. Its early strength is 5-10% higher than other Portland cements, and it has good frost resistance and wear resistance. It is suitable for the preparation of high-grade concrete and is used for more important civil engineering projects.
2, ordinary Portland cement
1) Concept
A hydraulic cementitious material made of Portland cement clinker, 6% to 15% mixed material, and appropriate amount of gypsum is called ordinary Portland cement, referred to as ordinary cement, code P·O.
The amount of the mixed material added depends on the amount of activity it has. According to the Chinese standard: if the active cement is mixed with active mixed materials (such as granulated blast furnace slag, volcanic ash, fly ash, etc.), the amount of addition should not exceed 15% by weight, and no more than 5% of kiln dust is allowed. (When the silicate cement clinker is produced by rotary kiln, the dust discharged from the kiln tail with the airflow, the dry powder collected by the dust collecting equipment) or not more than 10% of the inactive mixed material; the inactive mixture is added. The material must not exceed 10%. Ordinary cement is divided into six grades of 275, 325, 425, 525, 625 and 725, which are widely used in the manufacture of various mortars and concretes.
2) Technical requirements
The fineness requirement shall not exceed 10% of the 80um square hole sieve, otherwise it will be regarded as a non-conforming product. The initial setting time is no earlier than 45 minutes, and the final setting time is no later than 10 hours. The initial condensation is not satisfied as a waste product, and the final condensation is not satisfied as a non-conforming product. Volume stability must be qualified after inspection, otherwise it is waste. Ordinary Portland cement is divided into three strength grades, namely 32.5, 42.5, and 52.5, according to the compressive strength and flexural strength of 3d and 28d. Each grade is further divided into normal type and early strength type.
3) Basic performance and application
Ordinary Portland cement is basically the same as Portland cement in application, and there are some ordinary Portland cements that can not be used in Portland cement. This makes ordinary Portland cement the most widely used in the construction industry. The most used cement variety.
3. Slag Portland cement, pozzolanic Portland cement, fly ash Portland cement
Basic organic chemical raw materials:Calcium cyanamide, Dicyandiamide, Guanidine nitrate etc.
It is used for the manufacture of guanidine nitrate and sulfonamides in medicine. It is also used to produce thiourea, nitrocellulose stabilizer, rubber vulcanization accelerator, steel surface hardening agent, artificial leather filler, Adhesive and so on. The drug intermediate 5- aza cytosine can be obtained by the reaction of dicyandiamide with formic acid.As a raw material for guanidine and cyanogen two amines.
Organic Chemical Material,Dicyandiamide For Organic Chemical Material,Dcda For Organic Chemical Material,Superfine Dcda For Organic Chemical Material
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