Post-irradiation effects on Nylon-fibers reinforced concretes

Abstract

Fiber-reinforced concretes (FRCs) have a wider application range than ordinary concretes. Properties of FRCs necessarily depend on the characteristics of the aggregates used. We have studied first effects of gamma radiation on mechanical properties of hydraulic concretes containing Portland cement, silica sand, marble, water and Nylon fibers. Compressive strength and dynamic elasticity modulus are of particular importance. In the second stage we have analyzed the changes in these mechanical properties after storage of our concretes for three years. The long storage results in a 97 % of increment in the compressive strength and simultaneous lowering by 35 % of the dynamic elastic modulus. We find a larger influence of the Nylon fibers than those of silica sand and marble on mechanical properties of the concretes.

Nylon 6,12 fibers under low-dose gamma irradiation

“…It is worth noting that the fusion temperatures plotted are the mean values of at least two measurements. Similar periodic behavior (increment-decrement-increment and so on) have been obtained for composites containing nylon fi bers used in the present work [22,23] . It is recalled that with the exception of the value at 7 kGy, all irradiated samples exhibit higher values with respect to nonirradiating fi bers.…”

“…For nonirradiated concretes, the modulus decreases when adding more nylon fi bers. However, for irradiated fi ber concretes, two well-defi ned stages are distinguished: the values decrease from 5 to 10 kGy and they increase up to 100 kGy [23] .…”

Post-irradiation effects on gamma-irradiated nylon 6,12 fibers

“…This type of degradation coincides very well with other reports [20][21][22][23]. Also, little information is available regarding the post-irradiation effect on polyamides, particularly nylon 6,12 [7,12]. Based on this, the thermal behavior and superficial appearance of freshly irradiated (FI) fibers and fibers gamma-irradiated 6 years previously (6YI) were analyzed, with the aim of obtaining clues on the long-term effect of radiation on these macromolecules, in order to be able to predict their behavior in applications, like reinforcement in mortar and rebar concrete, as protective films, or forming composites or hybrid materials.…”

“…In addition to the basic research relevance of such studies, nylons have very attractive properties, such as excellent toughness, high tensile strength, abrasion resistance, chemical resistance, dimensional stability, excellent wet strength retention, and low tissue reaction [1]. By contrast, there is great interest in studying the radiation stability of polymers [2], as well as the change in chemical, mechanical and physical properties [3], aiming for future applications [4][5][6][7]. However, relatively few reports have been published on the effect of gamma radiation on nylons: mechanical properties [8], melting point decrease [9,10], degree of crystallinity [11][12][13], surface modification [14,15] and additional polymerization [9].…”

Smart Protection of Polymer-Inhibitor Doped Systems

“…32 In both cases it is estimated that with the proper release of the inhibitor and timely transportation of it, the steel corrosion rate will be significantly reduced.…”