Influence of moderately warm and extremely cold climate on properties of basalt plastic armature

Abstract

Rods of basalt plastic armature (BPA) of a periodic profile with diameters of 6, 8, 10, 16 and 20 mm on the basis of an epoxy matrix were exposed for 30 months on open stands in a moderately warm marine climate of Gelendzhik and 28 months on similar stands in an extremely cold climate of Yakutsk. For initial and exposed BPA samples, changes of mechanical parameters were determined. After the exposure in Yakutsk, an increase of ultimate compression strength by 4–12% is found, depending on the diameter of rods. After the exposure in Gelendzhik, this indicator decreases by 10–17%. Using methods of thermomechanical analysis and dynamic mechanical analysis, linear thermal expansion coefficient and glass transition temperature of epoxy matrix were measured. In an initial state, a transition from a glassy state to a highly elastic one is discovered: an α1-transition at 118 °C and an α2-transition at 149 °C. After climatic action, there were detected a shift of α1-transition to low temperatures and a shift of α2-transition to higher temperatures. Reasons for the change of temperatures of transitions are weakening of a molecular layer and post-curing of the epoxy matrix in a surface layer. These effects are accompanied by an increase of the linear thermal expansion coefficient, moisture diffusion coefficient and maximum moisture saturation after the climatic action on BPA. Fractographic studies discovered presence of pores in a structure of BPA with sizes up to 10–20 μm, a quantity and size of which increase by 20–40% after the climatic action. In general, the studied BPA has high climatic stability and can be used for a long time under the extreme climatic conditions.

Investigation of the Coefficient of Linear Temperature Expansion of Composite Rods and Heavy Concrete

“…The results of measurements given in Fig. 2, allow not only to justify high stability of the BPA in terms of thermal expansion, but also to evaluate the subtle effects of measured parameters for parallel samples in the initial state and after climatic tests in Gelendzhik [21] and Yakutsk. The results of thermal expansion measurements of BPAs are shown in Table 2.…”

“…shows the areas of increase and decrease of CLTR of initial (1) and after 51 months of exposure of 6 mm diameter (2) and 8 mm diameter (3).Temperature dependences of relative thermal expansion ∆ 0 ⁄ along the direction of reinforcement of BPA samples in the initial state and after exposure in Gelendzhik[21] and Yakutsk are shown inFig. 2.…”

Effects of hygrothermal aging on the thermomechanical properties of a carbon fiber reinforced epoxy sheet molding compound: An experimental research

“…Instead, it is proposed to use the minimum point of the temperature derivative of the storage modulus ( dE' / dT ) curve, based on the physical meaning that this point represents, that is, the maximum rate of the α‐transition 47 . Moreover, Startsev completes the T g analysis by plotting and checking the E' and E" curves 35,47–49 …”

“…47 Moreover, Startsev completes the T g analysis by plotting and checking the E' and E" curves. 35,[47][48][49] In this article, the plasticization effects generated by Type I hydrogen bonds have been analyzed by determining the variation in the T g values between dry and aged specimens. For this, the method proposed by Startsev et al 30 for stablishing T g has been employed and, at the same time, the suitability of this method for C-SMC materials has been validated.…”

The effects of aggressive environments on the mechanical properties of basalt plastics

“…Aging of BP under natural climatic conditions has not been studied well enough [1,24,52,53,54,55,56]. Some results of the study of effects of acid solutions on BF and BP properties are given in Table 7.…”