Strength, Drying Shrinkage, and Carbonation Characteristic of Amorphous Metallic Fiber-Reinforced Mortar with Artificial Lightweight Aggregate

This paper investigates the strength, drying shrinkage, and carbonation characteristic of amorphous metallic fiber-reinforced mortar with natural and artificial lightweight aggregates. The use of artificial lightweight aggregates has the advantage of reducing the unit weight of the mortar or concrete, but there is a concern that mechanical properties of concrete such as compressive strength and tensile strength may deteriorate due to the porous properties of lightweight aggregates. In order to improve the mechanical properties of lightweight aggregate mortar, we added 0, 10, 20, and 30 kg/m3 of amorphous metallic fibers to the samples with lightweight aggregate; the same amount of fiber was applied to the samples with natural aggregate for comparison. According to this investigation, the flow of mortar decreased as the amount of amorphous metallic fiber increased, regardless of the aggregate type. The compressive strength of lightweight aggregate mortar with 10 kg/m3 amorphous metallic fiber was similar to that of the LAF0 sample without amorphous metallic fiber after 14 days. In addition, the flexural strength of the samples increased as the amount of amorphous metallic fiber increased. The highest 28-d flexural strength was obtained as approximately 9.28 MPa in the LAF3 sample, which contained 30 kg/m3 amorphous metallic fiber. The drying shrinkage of the samples with amorphous metallic fiber was smaller than that of the sample without amorphous metallic fiber.

The Study of the Strength Properties of Galvanized Iron (GI) Fiber Reinforced Concrete

The use of concrete with randomly distributed metallic or non-metallic fiber is now prominent in concrete engineering and metallic fiber has been reported to have a better contribution to concrete mechanical properties. The utilization of locally available galvanized iron or metallic fiber as a bridging material which is a new technique in Bangladesh has the ability to surprisingly improve concrete physical properties. This research was, therefore, conducted to compare the concrete performance of GI fiber and steel fiber using previous literature as well as the suitability of GI fiber as a supplant to steel fiber in the concrete industry. This was achieved through the evaluation of the compression, tension, and brittleness of concrete with ‘Galvanized Iron’ fiber using several cutting lengths of 20 mm and 40 mm with multiple mix proportions including 1.0%, 1.5%, 2.0%, and 2.5% by volume of the concrete. The results showed the fiber with a large cut length of 40 mm and proportion lesser than 2.5% performed well than 20 mm with proportion 2% in reference to the plain concrete. Moreover, the incorporation of a 2.0% proportion of galvanized iron fiber with 40 mm length was observed to have exhibited crowning increment for both concrete compression and tension by 16.1% and 89.2% correspondingly contrasted to the control specimen. A further increase in the percent of fiber content 2% led to a reduction in the compression and tension for both 20 mm and 40 mm lengths while a significant reduction in brittleness for galvanized iron fiber reinforced concrete was observed in contrast to the control specimen. Furthermore, the inclusion of 1.0%–2.5% GI fiber with a 40 mm length reduced concrete brittleness by 56.9% - 65.5 % in comparison with the control specimen. Therefore, the inclusion of galvanized iron (metallic) to enhance the physical properties of concrete was deduced to be one of the startling stratagems

Mechanism of Electrical Conductivity in Metallic Fiber-Based Yarns

We explore the conductive mechanism of yarns made from metallic fibers and/or traditional textile fibers. It has been proposed for the first time, to our knowledge, that probe span length plays a great role in the conductivity of metallic fiber-based yarns, which is determined by the probability and number of conductive fibers appearing on a cross section and their connecting on two neighboring sections in a yarn’s longitudinal direction. The results demonstrate that yarn conductivity is negatively influenced to a large extent by its length when metallic fibers are blended with other nonconductive materials, which is beyond the scope of conductivity theory for metal conductors. In addition, wicking and wetting performances, which interfere with fiber distribution and conductive paths between fibers, have been shown to have a negative influence on the conductivity of metallic fiber-based yarns with various structures and composed of different fiber materials. Such dependence of the conductivity on the probe span length, as well as on the moisture from air and human body, should get attention during investigation of the conductivity of metallic fiber-based composites in use, especially in cases in which conductive yarns are fabricated into flexible circuit boards, antennas, textile electrodes, and sensors.