VietNamNet Bridge – Billions of dong have been spent to develop concrete block brick factories, as the investors believe unburned materials would be the “technology of the future.”

The Khang Minh Brick Company in the first quarter of 2013 reportedly received tens of orders on providing 30 million concrete block bricks to many big construction works in different localities. Under the contracts, the bricks with outstanding features, friendly to the environment, would be used to build workshops, industrial zones, workers’ dormitories in Hanoi, Bac Ninh, Hai Phong, Hai Duong and Ha Nam.

According to Dang Viet Le, President of Khang Minh, concrete block bricks are made of the two main materials including cement (8-10 percent), and grit. The products are adhesive and water proofing, which have high and stable quality because they are made with the modern production lines in an industrial scale.

At first, concrete block bricks were refused by contractors and architects, who said they were too heavy for high rise buildings. However, the products have gradually conquered the hearts of the experts.

In order to obtain the compress intensity of over 75 kg/cm2, they would need the 1,800 kg/m3 solid clay burned bricks. Meanwhile, they would only need the 1,400 kg/m3 hollow concrete block bricks to have the same intensity.

Some well known high rise buildings have been reportedly built totally with concrete block brocks, namely Keangnam Hanoi (70 storeys), Lotte (65), Hyundai HillStade (32), Nam Do Complex (28). The weight of the concrete block bricks, which were once considered a problem, has turned out to be helpful in keeping the construction works stay safe from the impacts of the outside force, such as wind, storm, or the changes in the temperature and pressure.

Experts believe that concrete block bricks are suitable for the construction works in Vietnam which use normal mortar. Mortar is made of cement and sand, while concrete block bricks are made of cement and grit. The two kinds of materials with similar characteristics allow to obtain the high adhesion for the construction works.

There is another outstanding feature of this kind of brick--that they can be re-used for many construction works. Thanks to the high compress intensity, the bricks can maintain their shape when construction works are demolished and can be re-used for other works.

Aware of the importance of the unburned construction materials, the government some years ago initiated the national program on developing unburned materials.

Encouraged by the government, investors have poured billions of dong to increase the designed capacity of unburned materials to 4.3 billion bricks a year, including 30-40 million concrete block bricks. Hundreds of small workshops have also geared up for the investment and production.

However, the prolonged frozen real estate market has put big difficulties for the investors. Unlike the lucky Khang Minh Company, brick workshops have complained that the products have been unsalable.

“Even the familiar kinds of bricks, which are used in 90 percent of the construction works, remain unsalable, let alone concrete block bricks, a new type of brick, which still cannot persuade consumers about its good characteristics,” a civil engineer commented.

There were 3 AAC brick manufacturers in the south, including Vuong Hai (V-block), Tan Ky Nguyen (E-Block) and Vinh Duc Saigon (BTONG), each of which had the capacity of 100,000 cubic meters per annum.

However, only V-block and E-block still keep operation, while BTONG has stopped production, now putting its production line on sale. Both V-block and E-block still can sell products, but they just keep the production at a moderate level.

Compiled by Thu Uyen