Build solid houses from clay

Cement is produced from clay materials, construction and industrial waste . Compared to traditional cement production technology, the cost of producing inorganic cement is only 50% and limited to 80 % of emissions.

This is the research result of Master Pham Tuan Nhi and colleagues at HCMC Geography Institute.

So far, clay has been used only as construction materials: bricks, tiles . or other types of pottery. But with polymer cement technology, clay does not stop at traditional use.

The price is only 600 - 800 VND per kg

Master of Pediatrics said, after taking up clay, the moisture is treated at 15%, forming blocks, burning at a temperature of 750 degrees C. After that, the soil is crushed, mixed with brick construction waste. , ceramics, debris and additives are becoming complete inorganic cement.

These additives are taken from seawater (MgCL ₂ ), furnace slag, fly ash ., substances with metal ions carrying chemotherapy II.

In construction, technicians cannot use sea sand, alum contaminated sand as aggregate. Because they do poor strength (compression, tensile strength) for concrete and mortar for portland cement.

However, the aggregates have disadvantages when combined with inorganic cement does not affect the quality of the construction. Therefore, it is very suitable for construction in sour and salty areas.

Dr. Chanh introduced products of inorganic cement to make earth concrete.Photo: T. Ngoc

Because it is not baked or only lightly heated (the concrete process will continue during use), the cement retains the original color of the soil. That brings a variety of colors of materials, facilitating the decoration.

Thanks to the solidity with all aggregates (including soil), it is applied in making rural roads but still has durability and high load, no less than concrete cement road is in use. use. Master Nhi revealed that he is carrying out construction of some road sections under this technology in Ca Mau and Dong Nai.

Thanks to the above advantages, cement finished products only cost from 600 to 800 VND per kg. Test results have shown that this cement is easy to use in acidic environments, withstand temperatures up to 1,200 degrees Celsius, which is considered better than portland cement being widely used.

Reducing environmental pollution

According to environmental experts, to produce a ton of Portland cement, the air must receive a ton of released CO2 from the calcination and burning coal process. Because limestone must be heated at temperatures above 1,200 degrees Celsius and for many hours.

Vietnam currently has 105 cement factories, with a total designed capacity of more than 61 million tons and the production output of factories in 2009 is estimated at 45-50 million tons, CO ₂ emissions are not small. .

According to Nhi's calculations, the process of inorganic cement production only burns at low temperatures, in a short time so emissions are only about 20% compared to traditional cement making. It also saves a significant amount of energy by using less fuel.

In particular, with the ease of curing soil, sand . with high compression, this is the ideal adhesive to produce unburnt construction materials, such as bricks, paving, tile, ceramics. , panel mounting .

Inorganic cement is also the ideal binder for concreting contaminated waste and radioactive waste. Also thanks to the advantages of not picky aggregate, it is easy to apply to making pottery, enamel, composite . that traditional cement still stands out.

Dr. Nguyen Van Chanh, Chairman of the Department of Construction Materials, Ho Chi Minh City University of Technology, said that inorganic cement technology in Vietnam has been studied for many years and also had initial success, but so far has not been applied.

In theory, in the laboratory, it is true that this type of cement has many advantages. But when put into practice, the problem must be solved is not small. According to Dr. Chanh, it is not necessary to be clay, but any material with a lot of aluminum oxide and free silicon oxide can make inorganic cement.

Mr. Do Trung Nam, Deputy Manager of Technology Management Department, Department of Science and Technology of Ho Chi Minh City, said: It is necessary to go through an appraisal committee, evaluate inorganic cement production technology. This technology must have many advantages over traditional cement and reduce environmental pollution.