In Vietnam, nano technology began to be interested in research and development, typically the seminar program of production research, silicon nano applications from waste materials and investment projects to build silicon nano manufacturing in Ho Chi Minh City. Researching the properties and applications of nano concrete in Vietnam with the desire to apply to some types of bridge and road structures today and step by step research on nano concrete application in designing some structure of bridges, roads, and other special works. With new materials used to determine the mechanical properties of materials and the characteristics of destruction at the limit of failure is essential. Moreover, high strength concrete materials are often brittle, so it is necessary to study measures to increase the plasticity to obtain the structure to ensure the requirements of the bearing and nano concrete with steel fibers. Steel fibers will make nano concrete increase tensile resistance in concrete.

The present study aims to investigate the effect of steel fiber addition on the behavior of the concrete beam in terms of crack formation, displacement, and deformation. The normal concrete (B20) was designed for making the beam with the target strength of 20 MPa. Different percentages of steel fiber (4% and 8% by volume) were added to the B20 mixture in order to evaluate the effectiveness of steel fiber addition to the concrete beams. The steel fiber concrete beams were subjected to the tests of crack formation, displacement, and deformation under loading. The numerical simulation by ANSYS computer software was also performed for comparison. As a result, the addition of steel fiber to the concrete beams was found to have positive effects as reducing both crack formation and the displacement as well as the deformation of the beams. Besides, the ANSYS modeling showed similar results as observed by the experiment.

Nano silicate SiO₂ (NS) in the high-performance concrete (HPC) mixture is becoming great interest because it improves the mechanical properties of concrete. As the ultra-fine SiO2 particles with a very high ratio of surface area to mass, NS can tightening the structure and produces better quality gel products and thus concrete strength increases. However, the optimal rate of NS in high-performance concrete has not been investigated. This study experimentally evaluates the influence of NS on compressive strength and flexure strength of HPC of which nominal strength is 70MPa. Seven mixtures of HPC at NS rate of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% over the total weight of the adhesive were conducted. Each mixture provides six samples for compressive tests and six samples for flexure tests. Total samples are 336 samples for four ages of concrete. Reliability of test results was carried out and results shown that at the early stage of HPC, an NS ratio of 1.5% shows the optimal value to improve the performance of concrete. This result also helps to apply NS in HPC in quality control in site application.

Wastewater pollution from domestic, industrial, and agricultural sources threatens the environment and human health. Traditional wastewater treatment methods are energy intensive, generate significant sludge, and may not remove all contaminants. This study explores the use of microalgae, Chlorella sorokinianana, to treat wastewater and evaluates its impact on concrete properties. The research aims to optimize microalgae growth conditions, set up nutrient‐rich growth chambers, develop biomass separation methods, and assess the effects of microalgae‐treated wastewater on concrete. Scanning electron microscopy (SEM) was used to analyze concrete structures produced with microalgae‐treated wastewater, freshwater, and sewage treatment plant (STP) water. Concrete from microalgae‐treated wastewater exhibited euhedral crystals with pronounced gaps, while freshwater concrete had denser subhedral to anhedral crystals. STP water concrete consistently had lower strength values, possibly due to impurities affecting cement hydration. Microalgae‐treated water concrete showed intermediate strength levels, suggesting organic or biological factors may influence hydration, but it still gained strength with time. This study underscores the potential of microalgae‐treated wastewater for sustainable concrete production, highlighting the importance of further research to optimize conditions and promote environmentally friendly construction practices.

In recent years in Vietnam, the structure of multi-storey buildings has been strongly developed in both quantity and quality, especially multi-storey buildings made from prefabricated reinforced concrete structures. Collecting documents shows that the Mekong Delta of southern Vietnam has built many multi-storey buildings using prefabricated reinforced concrete frame systems. In the southern climatic conditions, these multi-story buildings are directly affected by climate change, especially the seasonal wind load and the intensity of the wind is getting stronger and more complex, so the the work at the nodes of the frame will be affected. In this study, the authors studied the displacement of the frame system by horizontal displacement, vertical displacement, moment, shear and axial force of the frame according to three models: rigid linked frame, joint linked frame and semi-rigid linked frame.