Asbestos cement board is asbestos fibers and cement as the main raw material, its main advantage is thin, light, fire-resistant, waterproof, can be sawed, nailed, machining and assembly is relatively simple, with high flexural strength and crack resistance sex. In general, the flexural strength of 200 kPa (200 kg / cm in 1), up to 350 kPa (350 kg / cm pots). Its main disadvantage is that when the humidity changes, prone to decrease 20-30% larger warpage and cracking, impact strength after moisture than when dried. Asbestos cement board production than larger, in a conventional wall panel, second only to the gypsum board. According to incomplete statistics, the current world production of asbestos cement board manufacturers no less than 3000, the annual output has been more than two hundred million tons.
From a technical performance point of view, the development prospects of asbestos cement board is quite optimistic. However, in recent years, also we encountered a very difficult problem, and that is due to the presence of asbestos board production process pollution, harm to human health, resulting in the production in some countries it has strict limits.
Key to improving the performance of asbestos cement board technology is to prevent rear-sided sheet warping and cracking damp. There are two main ways: First, improve the production process, such as increasing the molding pressure, the use of sandy concrete instead of ordinary cement, maintenance and other high pressure. Second, in the surface of the sheet brushing waterproof layer such as acrylic waterproof coatings.