Research on fabricating flowforms from ultra-high performance concrete with local admixtures for use in processing contaminated water

In the recent years, flowforms have emerged as an effective natural aeration solution to provide dissolved oxygen (DO) for treatment processes of contaminated water. Flowforms are usually made from materials such as: cement, concrete, ceramic, glass, composite stone, metals… Among which, concrete and ceramic are most common due to the low production cost of the former and relatively good durability of the later. However, plain concrete has some disadvantages such as: heavy weight, difficult maintenance and prone to corrosion of the surface, i.e. peeling of fine aggregates on the surface resulting in loss of smoothness needed, while ceramic surface can develop cracks over time. Recent studies on ultra-high performance concrete (UHPC) with admixtures available in Vietnam such as silica fume and fly ash showed that, with high workability, this material would satisfy well the requirements for fabrication of flowforms in terms of smooth surface, high mechanical durability, corrosive resistance of finish product. The research team has successfully fabricated flowforms prototype from UHPC and tested it in practice. The test results on waste water in two years showed that UHPC has a distinct advantage over the most common materials in flowforms fabrication: it preserves the smooth surface, unlike the etched surface of cement or cracked surface of glass enameled ceramic (tested in same condition). In addition, flowforms made from UHPC also has the advantage in production cost, compared to ceramic and a good potential in reuse of industrial wastes. This article will cover the process of fabricating flowforms from UHPC with silica fume and fly ash admixtures as well as the results of testing flowforms prototype in waste water treatment.