Travertine Stone The gradation of the stone powder is characterized by the fineness (45 μm square sieve remainder). The fineness and specific surface area have a certain Travertine Stone conversion relationship, using fineness (45 μm sieve remainder) to characterize the gradation of the stone powder or the existence of theoretical defects, the test proved that when the scale of the stone powder surface to a certain extent, grinding fine stone powder to replace cement can achieve the effect of replacing cement strength with Shan grade fly ash, when the fineness of stone powder reaches nanometer grade, the material performance will change qualitatively. Therefore, it is more scientific to characterize the fineness of stone powder with specific surface area.
At present, most researches on the application of stone powder are focused on the challenge of limiting the content of stone powder, specifications more Travertine Stone requirements for the strength of concrete admixture, the resistance to cracking performance is obviously insufficient, the application of stone powder in concrete, the biggest problem is to reduce the crack resistance of concrete, such as the limit Travertine Stone tensile value of a large drop amplitude, the elastic modulus. The design of mass concrete should consider the anti-cracking performance as the first index, the maximum dosage of silica powder is 30%, and the effect of cracking resistance is too great through concrete test. At present, there are few cases of engineering application of adding 30% stone powder to mass concrete.
Surface modification technology is a kind of processing technology which uses chemical and physical methods to change the chemical composition or microstructure of the material surface to improve the properties of the material. There are four methods of surface modification: Travertine Stone mechanical chemical modification, coating method, coupling agent method and inorganic nano-cladding modification method.
At present, a lot of commercial concrete factories will stone powder and silica powder in the ball mill after mixing to replace the use of fly ash, the use of mechanical force to the surface of the two materials "melting" and synthesis, is the mechanical force chemical modification method of the original approach, although not standardized but the use of effective.
The surface modification of stone powder will play a revolutionary role in the application of stone powder in concrete, and give some surface effect to the stone powder. Travertine Stone For example, the surface of micro-activity, surface hydrophilicity, surface adhesion or particle excitation, and so on, can be used as a modified stone powder for the purpose of use, to improve the compactness of concrete, Travertine Stone mechanical properties, reduce hydration heat temperature rise, improve anti-cracking performance is advantageous.
According to the development of technology and engineering demand, it is very necessary to further study the technical specification of modified stone powder.
As a concrete admixture, limestone powder has its important characteristics: first, the pure limestone powder (clay content is low, high calcium carbonate content, water demand is low, can greatly reduce the volume of concrete units, the second, finer fineness, in the concrete can play a better role in micro-aggregate effect; The third, can greatly reduce the stickiness of high-strength concrete, reduce pump pressure, Travertine Stone improve the pump. To evaluate the quality of limestone powder, first of all, should look at its methylene blue value (MB value), MB value small, clay soil content is small, adsorption performance.