Grey target decision analysis of optimum mixing ratio of LWAS based on the comprehensive performance. (30th November 2020)

• Record Type: Journal Article
• Authors: Jin, Hesong; Xu, Haiyan; Yang, Shiyu; Xu, Ziyi; Li, Fuhai; Hu, Zhiming
• Is Part Of: Construction & building materials. Volume 262(2021)
• Publication Date: 2020-11-30
• Subjects: Tunnel engineering -- Lightweight aggregate shotcrete -- Orthogonal test -- Mechanical properties -- Durability -- Working performance -- Economic indicators -- Gray target decision; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.120570
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: According to the orthogonal experiment, the importance order of raw materials of LWAS are analyzed separately. A hybrid ellipsoidal gray target is defined, and on this basis, a mixed gray target decision model is established. The optimal mix ratio of LWAS is optimized by using grey target decision theory. Based on the method of mathematical statistics, the mix ratio of LWAS under the traditional orthogonal test is optimized. The application of research results in tunnel engineering is very good. Abstract: Aiming at the problems of complicated data processing, large amount of calculation, perplexing results of the orthogonal test, and the uncertain multi-index decision-making matter that the decision-making index value is difficult to be refined, this paper studies the mixed multi-index gray target decision-making model with three data types of real value, interval number and triangular fuzzy number. According to the basic connotation of decision gray target and uncertain decision information, a hybrid ellipsoid gray target is defined, and a mixed gray target decision model is established. Then through the mechanical, durability, workability and other performance, the lightweight aggregate shotcrete (LWAS) was selected for the optimization of the mix ratio, and then compared with the traditional orthogonal results, and applied in the tunnel engineering. Therefore, the feasibility of applying LWAS in tunnel bolting and shotcreting supporting was explored to provide a theoretical reference for the application of LWAS in tunnel lining. The results show that: (1). The unit water consumption has some influences on the compressive strength, Splitting tensile strength, bonding strength and resistance to chloride ion permeability of the LWAS, and the optimal range of water consumption is 180–200 kg/m 3 . (2). The water-binder ratio has a significant effect on the compressive strength, splitting tensile strength and electric flux of LWAS, and has a small effect on the bonding strength. (3). The compressive strength, splitting tensile strength and electric flux of concrete increase with the decrease of water-binder ratio. (4). When the fly ash content is 0%, the 28 d compressive strength, splitting tensile strength and bonding strength of LWAS are the largest, and the electric flux is the smallest. (5). When the water-cement ratio is 0.42 with pure cement, the combination of gray targets has the best comprehensive decision-making performance, and it is recommended as the tunnel lining concrete ratio.