1756, British engineer J. Smeaton found that in order to obtain hydraulic lime, limestone containing clay must be used for firing; The ideal composition of masonry mortar for underwater structures is made of hydraulic lime and volcanic ash. This important discovery laid a theoretical foundation for the research and development of modern cement.
1796, an Englishman J. Parker burned a kind of cement with marl, which was brown in appearance, much like a mixture of lime and volcanic ash in ancient Rome, and named it Roman cement. It is also called natural cement because it is made of natural marl and contains no ingredients. It has good hydraulic and rapid setting characteristics, and is especially suitable for projects in contact with water.
In 18 13, Gaby, a French civil engineer, found that the cement made by mixing lime and clay in a ratio of three to one has the best performance.
1824, British construction worker Joseph Astin invented cement and obtained the patent right of portland cement. He used limestone and clay as raw materials, mixed them in a certain proportion, calcined the mature materials in a vertical kiln similar to lime burning, and then made cement by grinding.
Because the color of hardened cement is similar to the stone used in construction in Portland, England, it is named Portland cement. It has outstanding architectural performance and epoch-making significance in the history of cement.
187 1 year, Japan began to build cement plants.
1877, crampton of Britain invented rotary furnace. 1885, Langsam transformed it into a better rotary furnace.
1889, near Kaiping coal mine in Tangshan, Hebei, China, Tangshan "fine cotton soil" factory produced by shaft kiln was established. 1906 Qixin lime company was established on the basis of this factory, with an annual output of 40,000 tons of cement.
1893, Hideyoshi Endo and Sanzhen Inland Sea of Japan invented portland cement that is not afraid of seawater.
1907, France Bie used bauxite instead of clay and mixed limestone to burn cement. This kind of cement is called "bauxite cement" because it contains a lot of alumina.
In the 20th century, while continuously improving the performance of portland cement, people successfully developed a batch of cement suitable for special construction projects, such as high alumina cement and special cement. There are more than 100 kinds of cement in the world, and the annual output of cement in 2007 is about 2 billion tons.
1952, China formulated the first national unified standard, and determined that cement production should be based on the principle of multi-variety and multi-label. According to its main mineral composition, Portland cement was renamed Portland cement, and later renamed Portland cement, which is still in use today.
In 20 12, the cement output in China reached 265,438+84 million tons, accounting for more than 50% of the global output.
Extended data
Function and function of cement
1, cementing material
As early as 300 years ago, ancient Egyptians and Romans were attracted by the reaction of volcanic ash and lime. After several centuries, many people have been inventing, testing and improving, forming today's cement technology and application system, and laying a theoretical foundation.
The early function of cement is cementing material, which is to bind gravel or bricks together firmly for a long time, and it is environmentally friendly and has low cost. Its bonding ability and durability are beyond the reach of any chemical gel material. It can be glued to stones, bricks, tiles, marble, etc.
2. Building structural materials
Reinforced concrete made of cement, sand and steel bars can be used in bridge engineering, tunnel engineering, coastal defense engineering, underground engineering and construction engineering, and can bear load, resist corrosion, freeze, high temperature and earthquake.
3. Waterproof material
Cement is not afraid of water, but it is compatible with water. It is closely related to water from beginning to end. Without the hydration of water, cement can do nothing. Cement can be used as a long-term and environmentally friendly waterproof material.
The capillary of cement has air permeability and plays a role in regulating water vapor. When it meets water, the capillaries will contract until they are completely locked, forming a barrier to prevent water molecules from passing through. People who are familiar with this characteristic of cement have developed waterproof mortar, plugging king, grouting material, repair mortar and so on.
4, thermal insulation materials
The density of cement mortar is about 1550- 1880kg/m3, and its thermal insulation is poor. However, after introducing air or combining with lightweight porous materials, the density is controlled at 120-270kg/m3, and the thermal insulation performance is good. Such as cast-in-place foam concrete, cement foam insulation board, cement foam self-insulation brick, lightweight insulation mortar, etc.
5, fire, refractory materials
Cement is an inorganic mineral incombustible material. Adding vermiculite, perlite, fly ash and other refractories can produce thick slurry for tunnels and steel structures, dry powder refractories with excellent environmental protection performance, and high-temperature burden.
6, masonry materials
Cement, ceramsite, industrial waste residue, volcanic ash, coal gangue, fly ash, etc. , can produce all kinds of lightweight perforated bricks, perforated bricks, steam-free curing bricks, etc.
7, plaster leveling materials
Cement can be used for ordinary screeding mortar, anti-crack mortar, putty for internal and external walls, etc.
8. Floor materials
Cement can be used in self-leveling ground, wear-resistant ground, terrazzo ground and other ground systems.
9, inorganic coatings, decorations
Use cement, coarse aggregate and fine aggregate, inorganic pigment, etc. It can produce decorative materials with different artistic styles, including smooth dry powder coatings and rough, vivid and abstract artistic coatings. Cement can also be made into artworks and handicrafts with different shapes and styles.
10, license plate
Cement, lightweight aggregate, light steel keel and steel wire mesh frame can be made into lightweight floors, partition boards and assembled houses with various specifications and shapes.
1 1, urban environment
Cement and ceramsite can be made into permeable bricks, porous bricks for urban sidewalks, porous bricks for parking lots and porous bricks for greening. Cement, steel wire and steel structure can also be made into urban sculptures, guardrails and wood-plastic products. Beautify the urban environment.
12, other aspects
Cement is also an essential material in military, aviation, nuclear industry, marine engineering, port construction and environmental protection engineering.
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