What Is Hypercementosis?

High alumina cement refers to a fast-hardening, high-strength, heat-resistant and corrosion-resistant cementitious material. Its main characteristics are early strength, high temperature and corrosion resistance. High alumina cement is mainly used for emergency construction projects, such as pressure prevention, roads and special repair projects, etc., and can also be used for winter construction projects. ^[1]

High alumina cement

High alumina cement (formerly

Label

The designation of high alumina cement is the strength specified in this standard.

1. Fineness

According to GB1345-77 "Cement fineness inspection method (sieve analysis method)"

2.

1. Early strength characteristics: Its early strength improvement rate far exceeds that of fast-hardening portland cement, which is suitable for emergency repair works, but its strength will be reduced in the later period, which limits its use in structural engineering.

2. The heat of hydration is large: In the early period of hardening, the heat of the cement is large. Compared with the same-named portland cement, 70% to 80% of the total heat of hydration can be released in one day. Due to several kinds of heat release, it is suitable for low temperature curing concrete projects.

3, strong resistance to sulfate attack: hydration process does not precipitate free calcium hydroxide but instead generates aluminum hydroxide gel, forming a protective film on the particle surface. The erosion resistance is reduced during the later crystal transformation process.

4. Good high temperature resistance: High alumina cement can be used as a cementing material for heat-resistant concrete and configured as heat-resistant concrete. ^[2]

1. Numbering and sampling

The cement is numbered and sampled according to the same label before leaving the factory. Each number is a sampling unit. One number must not exceed 100 tons. Cement plants with a daily output of less than 100 tons should be sampled with a number not exceeding the daily output as a sample. It can be taken continuously or an equal amount of samples can be taken from more than 20 different parts, with a total weight of at least 15 kg.

Note: After the serial number sampling, the cement must be re-sampled after leaving the factory for more than 15 days, and this sample shall prevail.

2. Inspection and sample retention

The cement samples obtained for each number should be thoroughly mixed and divided into two equal parts. One is inspected by the cement factory in accordance with the methods specified in Chapter III of this standard; the other is kept in a sealed container for two months for submission to the inspection agency designated by the state for re-inspection or arbitration when in doubt.

3 Factory cement

The quality of ex-factory cement must meet the requirements of each index in Chapter 2 of this standard.

4 Inspection Report

The cement factory shall send a cement quality inspection report within 6 days from the date of cement issuance. The report shall include the test results listed in Chapter 2 of this standard, and shall be accompanied by the quality standard and the date of manufacture of the cement. If requested by the user, the 28-day strength results and alumina,

1. package

Moisture-proof in cement bags

1. Transportation and storage

High alumina cement should be protected from moisture during transportation and storage, and must be stored and transported separately from other types of cement, and must not be mixed.

2. The main purpose

(1) Preparation of amorphous refractories.

(2) Preparation of special-purpose cement such as gypsum bauxite expansion cement and self-stressing cement.

(3) Projects with special needs such as rush construction, rush repair, resistance to sulfate attack and winter construction.