Effect of fiber content and stress–strength ratio on the creep of basalt fiber–reinforced alkali‐activated slag concrete

Abstract

Alkali‐activated materials are increasingly being used in practical applications as potential alternatives to Portland cement. If alkali‐activated slag (AAS) is to be applied to prestressed engineering and large‐size structures, it is necessary to study the creep performance of AAS. Existing studies have found that the creep of AAS concrete is larger than that of ordinary Portland cement (OPC) concrete, and adding fiber is an effective way to overcome this defect. In this study, we investigated the creep of basalt fiber–reinforced AAS (FRAAS) concrete for fiber contents ranging from 0% to 0.9% (by volume) at a stress–strength ratio of 0–0.6. After analyzing the experimental results, it was found that the basalt FRAAS concrete had no obvious linear creep range. It was observed that with an increase in the fiber content, the inhibition effect of fiber on creep became stronger initially and then weaker. The inhibitory effect of fiber on creep was strengthened by the increase in the stress–strength ratio. The creep coefficient showed no obvious change when the fiber content was in the range of 0%–0.9%. Based on the existing OPC concrete creep models, a method for predicting the creep of basalt FRAAS concrete was proposed.

Influences on the mechanical and physical properties of hot-press moulding alkali-activated slag (HP-FRAASC) composite with various fibers

“…The incorporation of fibres as the primary reinforcement for slag-based polymers, regardless of fibre type, aims to provide higher resistance to crack formation and expansion to overcome this weakness directly [21–24,35,37,39–41,43,44]. The following mechanism can explain this phenomenon: When the specimen is subjected to a bending load, the tensile stress is caused by the bending moment at the interface between the fibre and the matrix into shear stress and through the interface with the matrix bonding and friction to offset [40,41,45,47]. This contact effect is not only in the interface of the two components but also in the far away from the interface so that the joint action of the fibre and the matrix forms a kind of ring area, thereby increasing the load-bearing capacity of the interface [45].…”

“…Next, some fibres deboned because the energy required for crack expansion exceeds the bond strength between these fibre types and the matrix, and some of these fibres cross the cracked area in the form of bridging. Currently, the main types of these high-performance fibres or reinforcements are as follows: steel fibres [36–49], carbon fibres [50–56], poly-tetrachloroethylene (PTFE) fibres [21–33], glass fibres [22–26], and basalt fibres [21,27,28].…”

“…Researchers have also investigated the performance of these fibres incorporated into the matrix [36–55]. Bernal et al [36] analysed the mechanical and permeability properties of alkali-activated slag concrete (AASC) reinforced with steel fibres early and evaluated its compressive, splitting tensile and flexural strengths, flexural notch sensitivity, pullout, and water absorption properties.…”

Influence of fiber characteristics on sulfate resistance of ambient‐cured geopolymer concrete

“…Fibers are used extensively in concrete production in order to controlling plastic shrinkage cracking of concrete 9,16,39,51 . It is aimed to improve the brittle characteristics of concrete such as crack formation resistance, weak tensile and flexural strength with fibers 9,52,53 . Natural and synthetic fibers such as glass, polypropylene (PP), basalt, steel, carbon are usually added to mixture as percentage of concrete volume 16,37,51,54 .…”

“…9,16,39,51 It is aimed to improve the brittle characteristics of concrete such as crack formation resistance, weak tensile and flexural strength with fibers. 9,52,53 Natural and synthetic fibers such as glass, polypropylene (PP), basalt, steel, carbon are usually added to mixture as percentage of concrete volume. 16,37,51,54 PP fiber is the most popular one among all fibers.…”