No abstract

In this paper, the influence of solvents and reinforcement processing methods on the mechanical properties of nanocomposite poly-(methyl methacrylate) PMMA-Ti3C2Tx MXene was investigated. A weight fraction of reinforcement was 1% and two types of solvents were used for sample preparation: dimethylformamide (DMF) and acetone (Ac). Deionized water and DMF were used to delaminate the MXene. An additional peak at 1675 cm-1 was observed on the FTIR spectra of the obtained samples, which indicates that some amount of DMF remained in the material after drying. The results of microindentation show that samples where MXene was delaminated in deionized water and PMMA dissolved in acetone had a 74.46% higher reduced modulus of elasticity, which is supported by SEM images where better dispersion of MXenes is observed.

This paper describes the calculation of the fi re resistance of reinforced concrete column that is exposed to fi re from two sides. Calculation of the temperatures has been made depending on whether the heat fl ow within the reinforced concrete column is onedimensional or two-dimensional. The temperature of concrete and the temperature of reinforcement are calculated by the Hertz's method. The values of concrete strength and reinforcement, as well as the width of the damage zone of concrete during a certain period of exposure to fi re have been calculated. Resistance to the effects of fi re on reinforced concrete column has been calculated by the zone method. The time of the resistance of column to the effects of fi re has been determined according to the moment capacity of reinforced concrete column.