Doan Phuoc Thinh and Phan Vo Ky Duyen, both 9^th graders of the Pham Ngoc Thach Junior High School in Son Tra District, Da Nang, have researched and implemented a project on making unburnt bricks from clam shell waste and styrofoam that not everyone at their age can think of and start doing.

Thinh and Duyen presented on the topic "Making unburnt bricks from clam shell waste and styrofoam in Son Tra coastal urban area"

The project aims to produce construction materials from waste by-products available in abundance in Son Tra District instead of such raw materials as clay, limestone, sand, gravel and cement. And more importantly, such production neither pollutes the environment nor depletes natural resources.

After researching alternative sources of raw materials, the pupils realized that clam shells are mainly composed of limestone and foam which are durable, light, and convenient. Therefore, they decided to embark on the project "Making unburnt bricks from clam shell waste and styrofoam in the coastal urban area of ​​Son Tra".

They informed that besides the positive side of seafood exploitation in Son Tra District, the negative side of this problem is that it has been and is creating a huge amount of waste from the shells of bivalve mollusks such as clams, mussels, and oysters. Although this type of "waste" will decompose over time in the long run, in the short term, it still requires a lot of space and effort to bury and process.

In addition, another type of waste that is also very common in life as well as in the exploitation and consumption of seafood processing is styrofoam boxes.

Witnessing the image of clam shells being dumped along with styrofoam food boxes scattered everywhere from the Tho Quang Seafood Wholesale Market to the Man Thai Afternoon Market, then at restaurants, seafood eateries and beaches, makes the Son Tra sea environment less beautiful and clean in the eyes of tourists. This motivates the pupils to find useful solutions to utilize these two types of waste.

To get started, Thinh and Duyen learned that making quicklime (CaO) from the shells of bivalve mollusks by heating at high temperatures of 950oC or higher will release a lot of toxic CO2 gas. In addition, plastic waste has also been studied to make garden bricks when heated with quicklime. However, the process of heating plastic waste with quicklime also creates serious environmental problems due to CO2 emissions. Meanwhile, thanks to modern technology, agricultural by-products that were once proposed to make bricks such as straw, rice husks, bagasse, corn cobs, corn stalks, etc. are being processed into energy pellets, so they are no longer a worrying waste. From those observations, the pupils focus on turning the huge source of waste typical of the coastal urban area of Son Tra into useful building materials.

Thinh and Duyen, under the enthusiastic advice of teacher Vo Thi Thuy Lan, created 4 sets of brick samples mixed with different proportions of raw materials, with each sample corresponding to different mixing formulas, corresponding to the colors gray, pink, yellow and blue, then conducted a survey of the physical properties of the brick samples.

After comparison, analysis and conclusion, the most optimal result was the M2 brick sample. From there, the study confirmed the high feasibility of using clam shells and foam to make unburnt bricks.

After days of research and hard work, the brick samples were completed and sent for testing at the Soil Mechanics and Construction Materials Laboratory of M.I.T.C.O Construction Inspection and Consulting JSC for physical and mechanical properties. The results showed that all samples were higher than the standard VN 6477: 2016 issued by the Ministry of Construction.

The joy was overwhelming when the pupils' project won the first prize in the Son Tra District-level Science and Technology Competition for Junior High Schools, and the four prize at the municipal-level Science and Technology Competition for Junior High Schools, during the 2024-2025 academic year.

Reporting by DAN HUNG - Translating by M.DUNG