Influence of industrial solid waste as filling material on mechanical and microstructural characteristics of cementitious backfills

Li, Jiajian; Yılmaz, Erol; Cao, Shuai

doi:10.1016/j.conbuildmat.2021.124288

Cited by 71 publications

(12 citation statements)

References 55 publications

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“…Baotou is one of the pilot WFCs in Inner Mongolia, China. Moreover, FA and gypsum are the two main types of solid waste in Baotou [11]. Thus, the utilization of SWs has become a hot research topic in this city.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Macro Mechanical Properties and Microstructures of Cement-Based Composites Prepared from Fly Ash, Gypsum and Steel Slag

Cao

Yılmaz

2021

Minerals

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Using solid wastes (SWs) as backfilling material to fill underground mined-out areas (UMOAs) solved the environmental problems caused by SWs and reduced the backfilling cost. In this study, fly ash (FA), gypsum and steel slag (SS) were used to prepare cement-based composites (CBC). The uniaxial compression, computed tomography (CT) and scanning electron microscope (SEM) laboratory experiments were conducted to explore the macro and micromechanical properties of CBC. The findings showed that the uniaxial compressive strength (UCS) of CBC with a curing time of 7 d could reach 6.54 MPa. The increase of SS content reduced the UCS of CBC, while the gypsum and FA content could increase the UCS of CBC. Microscopic studies have shown that the SS particles in CBC have noticeable sedimentation, and the increase of SS content causes the failure mode of CBC from tensile to tensile-shear. These research results can provide a scientific reference for the preparation of backfilling materials.

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Section: Introductionmentioning

confidence: 99%

Characterization of Macro Mechanical Properties and Microstructures of Cement-Based Composites Prepared from Fly Ash, Gypsum and Steel Slag

Cao

Yılmaz

2021

Minerals

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“…The results showed that crushed waste oyster shells replaced 30% of the fine aggregate, and 30% of the cement was replaced by fly ash and ground granulated blast-furnace slag to obtain the mortar with the best performance. Li et al [10] studied the feasibility of industrial solid wastes (fly ash, desulfurization gypsum, steel slag) as mineral filler materials through experiments, which solved the environmental risks caused by industrial solid waste and reduced the cost of cement-based cementitious materials. Ju et al [11] proposed a precipitation-solvent extraction-leaching process, which can effectively separate and recover titanium, scandium, and iron in acidic wastewater and realize the resource utilization of red gypsum.…”

Section: Introductionmentioning

confidence: 99%

Research on the Performance of Titanium Gypsum Concrete Based on Calcium-Silicon-Sulfur Ratio

Guo¹,

Wang²,

Zhong³

et al. 2023

Journal of Renewable Materials

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Based on the high sulfur content in titanium gypsum, the concept of the calcium-silicon-sulfur (Ca/Si/S) ratio was proposed. The Ca/Si/S ratio of concrete was adjusted by changing the titanium gypsum, fly ash, and cement content. The effects of different Ca/Si/S ratios on the mechanical properties, hydration products, and concrete microstructure were investigated by nuclear magnetic resonance, uniaxial compression, and scanning electron microscopy. The result shows: (1) The compressive strength of concrete mixed with titanium gypsum increases first and then decreases with the Ca/Si/S ratio decrease. When the Ca/Si/S ratio is 1:0.85:0.10, the strength reaches the peak and is lower than the blank group. (2) The microstructure indicates the addition of titanium gypsum can effectively stimulate the activity of fly ash. Still, too much or too little titanium gypsum will hamper concrete strength development. (3) Titanium gypsum concrete's nuclear magnetic resonance T2 spectrum has two characteristic peaks. With the Ca/Si/S ratio decreasing, the micropores in the concrete expand towards the macropores. The compressive strength is negatively correlated with the proportion of macropores and is positively correlated with the proportion of no-capillary pores.

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“…There are some clear differences between CPB, mortar and concrete (Benzaazoua et al, 2004). Fresh and hardened characteristics of CPB is quite different from those of mortar and concrete (Li et al, 2021). This means that the amount of the water used within CPB is far more than the chemical binding capability of OPC within CPB, thereby leading to slow acquisition in the strength and low strength, especially for early ages.…”

Section: Introductionmentioning

confidence: 99%

Strength Analysis and Optimization of Alkali Activated Slag Backfills Through Response Surface Methodology

Dai

Ren

et al. 2022

Front. Mater.

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The significant difference in water-to-binder ratio, activator type and concentration between alkali-activated slag (AAS) paste/mortar/concrete and AAS-based cemented paste backfill (AAS-CPB) means that previous results related to the properties and mix optimization of AAS materials cannot be directly translated to AAS-CPB. This study statistically identifies the effect of key influential variables such as silicate modulus, slag fineness and activator concentration on 3- and 28 day unconfined compressive strength (UCS) of AAS-CPB by central composite design (CCD) established in response surface methodology (RSM). In this study, the prominence of independent variables and their relations are investigated by using ANOVA (analysis of variance) having a significant level of 0.05. ANOVA results certify that there is a strong link between the level of variable contribution on UCS performance of AAS-CPB and curing age. Obviously, silicate modulus and activator concentration are the most major variables influencing UCS at 3 and 28 days, respectively. Increased fineness of slag and higher pH of pore solution enhance 3 day UCS, but restrain the further hydration of unreacted slag and subsequent the gain in strength at advanced curing ages. The combination of independent variables of silicate modulus (0.295), slag fineness (12630.2), activator concentration (0.45) gives the optimum responses.

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Influence of industrial solid waste as filling material on mechanical and microstructural characteristics of cementitious backfills

Cited by 71 publications

References 55 publications

Characterization of Macro Mechanical Properties and Microstructures of Cement-Based Composites Prepared from Fly Ash, Gypsum and Steel Slag

Characterization of Macro Mechanical Properties and Microstructures of Cement-Based Composites Prepared from Fly Ash, Gypsum and Steel Slag

Research on the Performance of Titanium Gypsum Concrete Based on Calcium-Silicon-Sulfur Ratio

Strength Analysis and Optimization of Alkali Activated Slag Backfills Through Response Surface Methodology

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