The reason why sea sand can not be used as building sand and gravel detailed explanation
sand and gravel is the foundation of construction and various engineering facilities, and plays a decisive role in production activities. In recent years, in order to protect the environment and ecological balance, the state has increased the control of natural sand and strictly managed the exploitation of natural sand. In addition, there has been a recent period of environmental supervision. These factors have led to a shortage of sand and gravel in the recent market, The price of sand and stone is rising, so some people, driven by their interests, take advantage of China's worrying competitiveness in this field to mix unqualified sand and stone into the market, resulting in a certain amount of sea sand and other non-conforming sand in the market, and carry out lightweight technology exchange with visiting experts
flocking like materials can reduce the pollution caused by spraying or printing and dyeing that originally achieved the effect of imitation kapok.
it is well known that unqualified sand and stone enter the construction process, which is very harmful. Therefore, all localities have increased their efforts to crack down on unqualified sand and stone. Recently, Shanghai sand and Stone Association issued a notice requiring that the production, sales and use of sea sand in the concrete and prefabricated components fields in Shanghai should be prohibited, It is absolutely not allowed to be used in the production of concrete and dry mixed mortar
why is the society so sensitive to the use of sea sand? What is the harm of sea sand that must be prohibited
we all know that most of the buildings in cities are reinforced concrete structures. This is because the combination of reinforcement and concrete can achieve the best performance, and the durability is relatively strong. The raw material of concrete is cement. The composition of cement is estimated to be tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium ferroaluminate. After hydration reaction, the concrete is the most alkaline, while the reinforcement is in a strong alkaline environment, It will be oxidized, and a protective film composed of hydrated ferric oxide will be formed on the surface. This protective film is very important. It can isolate the reinforcement from the external environment, prevent the reinforcement from contacting water and oxygen, and reduce the effect of oxidation and corrosion, so as to protect the reinforcement
next, the key point is why sea sand is not allowed to be used in buildings. This is because this substance contains chlorine salt, and the chloride ion in the chlorine salt will penetrate through the protective film, react with the reinforcement, corrode the reinforcement, and lead to the corrosion of the reinforcement. In the long run, the durability of the concrete structure will become worse, resulting in the cracking of the reinforced concrete floor, the cracking of the wall, and even the collapse of the building
there is a shortage of natural sand and the use of sea sand is prohibited. Therefore, machine-made sand is quietly emerging in the market. It is a kind of sand processed by sand making machines and other equipment. Machine-made sand has many advantages. First, the finished sand produced by machine-made sand is more regular and can be processed into Sands of various rules and sizes according to requirements to meet different needs. The disadvantage is that it requires professional equipment and high investment cost