Effect of TiO2 on preparation condition, mechanical properties and alkali resistance of continuous basalt fibers. (February 2023)

• Record Type: Journal Article
• Authors: Dou, Haoyu; Bai, Jin; Lu, Hao; Zhang, Tingting; Kong, Lingxue; Bai, Zongqing; Li, Wen
• Is Part Of: Cement & concrete composites. Volume 136(2023)
• Publication Date: 2023-02
• Subjects: Continuous basalt fiber -- Alkali resistance -- TiO2 -- Tensile strength -- Fiber reinforced concrete; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2022.104861
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: The low alkali resistance of basalt fiber limits its utilization in the strong alkaline environment such as cement and concrete as the reinforcing material. Adding additive in the basalt rocks is the feasible method to enhance the alkali resistance. However, it is necessary to develop the efficient additive for basalt fiber. In this work, the effect of TiO2 on the preparation condition, alkali resistance and mechanical properties of basalt fiber was investigated. The preparation conditions were studied by DSC, XRD and high-temperature rotational viscometer. Then the corrosion behavior of TiO2 -basalt fibers in NaOH solution was studied via SEM/EDX, FIB/SEM and FTIR. The results indicated that the viscosity of basalt melt decreased significantly with the increasing TiO2 content from 0% to 2%, but the crystallization tendency was not changed with TiO2 below 2%, the upper limit for TiO2 addition. The tensile strength increased by 20–60% because Ti 4+ promoted Al 3+ into the network structure and intensify the polymerization by entering the network structure as network precursor in the form of [TiO4 ]. Meanwhile, TiO2 in the basalt fibers formed insoluble titanium hydroxide, so the weight loss of TiO2 -basalt fibers in NaOH solution was reduced up to 50%. Through FIB/SEM/EDX, the corrosion of basalt fiber in alkali condition is controlled by ion diffusion. The outward diffusion of Fe, Mg and Ti to the surface of fiber formed the insoluble layer, so the rate of substitution reaction between the OH − and basalt fibers was slowed down, but it also leaded to the non-uniform corrosion. Highlights: Effect of TiO2 on alkali resistance of BF was firstly investigated systematically. TiO2 -BFs with excellent alkali resistance were obtained. The tensile strength of TiO2 -BFs increases by 22–58%. Non-uniform corrosion of BF in alkaline solution was directly observed by FIB/SEM.