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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. [ABSTRACT FROM AUTHOR]

• Forty-two specimens were design to test compressive and flexural behaviors. • Two calculation methods were utilized to evaluate compressive toughness performance. • Four methods form standards were utilized to evaluate flexural toughness performance. • The optimal content of BF and PANF were suggested respectively. To study the effects of fibers on the compressive and flexural toughness of lightweight aggregate concrete (LWAC), an experimental investigation of fiber-reinforced LWACs subjected to compressive and flexural loading conducted. In the study, basalt fibers (BFs) and polypropylene fibers (PANFs) are used as the reinforcing materials in 0.5%, 1.0%, and 1.5% volume fractions. The test results show that, except LYB0.5, BFs and PANFs can improve axial compressive strength, and BFs exhibit better improvement effect than PANFs under the same volume fraction. Moreover, compared to the plain LWAC specimen, the LWACs with BF and PANF reinforcements present better compressive stress–strain and flexural load–deflection behaviors, and the descending branches of these plots become curved with fiber addition. Additionally, the energy ratio method and the critical stress method are utilized to calculate the compressive toughness behaviors of the LWACs, respectively. And the calculation results demonstrate that at a particular fiber volume fraction, BFs improve the compressive toughness more than PANFs due to the higher tensile strength and elastic modulus. Moreover, energy ratio method is suggested to calculate compressive toughness. In addition, four methods from different standards are utilized to evaluate the flexural toughness behaviors of the LWACs. The comparative analysis results exhibit that the methods from ASTM C1609, JSCE SF-4, and JG/T 472-2015 can be used, whereas that from ASTM C1018 leads to some errors originating from the inaccurate determination of the first crack station of specimens. And specimen with 1% BF or 1.5% PANF are suggested to improve the flexural toughness behavior of LWACs respectively. [ABSTRACT FROM AUTHOR]

In this study, an experimental investigation was conducted on the mechanical properties of lightweight aggregate concrete (LWAC) with different chopped fibers, including basalt fiber (BF) and polyacrylonitrile fiber (PANF). The LWAC performance was studied in regard to compressive strength, splitting tensile strength and shear strength at age of 28 days. In addition, the oven-dried density and water absorption were measured as well to confirm whether the specimens match the requirement of standard. In total, seven different mixture groups were designed and approximately 104 LWAC samples were tested. The test results showed that the oven-dried densities of the LWAC mixtures were in range of 1.819–1.844 t/m3 which satisfied the definition of LWAC by Chinese Standard. Additionally, water absorption decreased with the increasing of fiber content. The development tendency of the specific strength of LWAC was the same as that of the cube compressive strength. The addition of fibers had a significant effect on reducing water absorption. Adding BF and PANF into concrete had a relatively slight impact on the compressive strength but had an obvious effect on splitting tensile strength, flexural strength and shear strength enhancement, respectively. In that regard, a 1.5% fiber volume fraction of BF and PANF showed the maximum increase in strength. The use of BF and PANF could change the failure morphologies of splitting tensile and flexural destruction but almost had slight impact on the shear failure morphology. The strength enhancement parameter β was proposed to quantify the improvement effect of fibers on cube compressive strength, splitting tensile strength, flexural strength and shear strength, respectively. And the calculation results showed good agreement with test value. [ABSTRACT FROM AUTHOR]

• The bamboo fiber used in the anti-slide pile can play the role of crack resistance. • The anti-slide pile with 1% volume ratio of bamboo fiber can achieve better flexural and crack resistance. The optimal dosage for bamboo fiber with rebars is 0.5%. • The optimal aspect ratio of bamboo fiber is between 16.7 and 23.3. • The rapid development of microcracks in anti-slide piles can be restrained effectively by the uniform distribution of bamboo fibers with appropriately small aspect ratio and volume ratio. In order to avoid cracks in anti-slide piles and thus causing brittle damage, incorporating fibers in anti-slide piles to improve their ductility is an effective way to enhance the crack resistance. Bamboo fiber, as a low carbon fiber material, has good crack resistance and toughening effect, and can be used as a new concrete reinforcement material to enhance the crack resistance of anti-slide piles. In this paper, the load–displacement relationship, deformation and cracking characteristics of 28 bamboo fiber-reinforced concrete anti-slide piles are studied considering the aspect ratio, fiber dosage and its coupling effect with rebars. The main conclusions of the study are as follows: (1) The bamboo fiber used in the anti-slide pile can play the role of crack resistance. The plain anti-slide pile produces one main tension crack and full-section fracture failure, while the anti-slide pile with the coupling effect of bamboo fiber and rebars suffers from diagonal section instability failure with one main diagonal tension crack and several secondary cracks. (2) The anti-slide pile with 1% volume ratio of bamboo fiber can achieve better flexural and crack resistance. The optimal dosage for bamboo fiber with rebars is further reduced, which is 0.5% (3) The optimal aspect ratio of bamboo fiber is between 16.7 and 23.3, which can improve the flexural performance of anti-slide piles, but the aspect ratio of bamboo fiber fails to essentially change the failure mode of anti-slide piles. Fiber dosage has a significant effect on the cracking failure mode of anti-slip piles. The rapid development of microcracks in anti-slide piles can be restrained more effectively by the uniform distribution of bamboo fibers with appropriately small aspect ratio and volume ratio. [ABSTRACT FROM AUTHOR]