•GBFS, UCG and MFASB were used to synthesis the ternary OAGM.•Effects of various factors on flowability, setting time and strength were studied.•Borax is the optimal retarder for the ternary ...OAGM.•The ternary OAGM with BR has high compressive strength and great flowability.•Reaction product, microstructure and pore structure of different OAGMs were studied.
To obtain an environment-friendly grouting material suitable for in situ application, the granulated blast furnace slag (GBFS), uncalcined coal gangue (UCG) and microscopic fly ash sinking beads (MFASB) were used to synthesis the one-part alkali-activated grouting material (OAGM). Firstly, OAGMs with different combination of precursors were prepared respectively, which are GBFS-based OAGM (the unitary OAGM), GBFS/UCG-based OAGM (the binary OAGM) and GBFS/UCG/MFASB-based OAGM (the ternary OAGM). The flowability, setting time and compressive strength of them were measured to analyze their applicability and feasibility in grouting engineering and obtain the OAGM with a reasonable combination of precursors. Next, the effects of different water to solid ratios (W/S ratios), different retarders, and the content of selected retarder on the OAGM were investigated to put forward its rational composition under the best overall performance. Finally, the reaction product, microstructure and pore structure of OAGMs were characterized to probe into their mechanism. Results show that compared with other OAGMs, the ternary OAGM with the retarder borax (BR) has the best overall performance. This material not only has the best flowability and the longest setting time, but also has high compressive strength, thus, it is more suitable for grouting engineering. Microstructural tests reveal that adding UCG and MFASB sequentially into GBFS-based OAGM makes important impacts on the formation of C-A-S-H gel, thus affecting the compressive strength. And adding MFASB into the binary OAGM increases the harmless pores, causing the ternary OAGM has higher porosity. However, the increase of porosity does not necessarily bring about the decrease of compressive strength. Besides, pore structure characteristics shows that adding BR increases the porosity of the ternary OAGM. This study can provide guidance for preparing environment-friendly OAGM suitable for in situ application and promote the recycling of industrial solid wastes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To promote the application of warm mix asphalt (WMA) technology in strong UV areas, warm mix SBS modified asphalt binders with better UV aging resistance were developed in this study. The ...conventional physical properties, viscosity-temperature characteristics, rheological properties and storage stability were carried out to analyze the performance of the prepared modified asphalt containing Sasobit and OMMT. Then, TOPSIS method was selected for multi-index optimization to optimize the dosage of OMMT and Sasobit. Subsequently, the warm mix effect, high temperature property and aging resistance of the developed modified asphalt were further evaluated. Finally, the modification mechanism was characterized with FTIR, XRD and FM. Test results show that, Sasobit can significantly improve the construction workability of asphalt, and OMMT can enhance the storage stability and UV-aging resistance. In addition, the two modifiers can both improve the high temperature property of SBS modified asphalt. Based on the multi-index optimization results, it is recommended that the optimal dosage of Sasobit and OMMT is 3% and 2%, respectively. And microstructure characterization test results reveal that the asphalt chains and polymer molecules have been successfully intercalated into the layers of OMMT molecules, and further the exfoliated structure has been formed in the composite asphalt blend, thus improving its road performance. From the above results, it can be concluded that both additives play their own advantages at their optimum dosages.
•Warm mix asphalt with better aging resistance was developed.•Optimum dosages of modifiers were obtained based on multi-index optimization.•The modification mechanism of asphalt was evaluated by FTIR, XRD and FM.•Exfoliated structure has been formed in the composite asphalt blend.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
As a promising sustainable building material, geopolymer/steel-slag composite materials have been poorly known in the field of the interfacial characteristics of geopolymer/steel-slag interface, ...especially at the molecular level. Herein, in this work, molecular dynamics simulation was employed to reveal the interfacial characteristics and mechanical behaviors of geopolymer binder with steel slag aggregate. The molecular models of two geopolymer binders (C-A-S-H and N-A-S-H) and three main minerals of steel slag aggregate (Ca2SiO4, Ca2Fe2O5 and CaCO3) were constructed and carried out. Then the wetting characteristics of different mineral surfaces, interfacial characteristics, interaction mechanisms and mechanical behaviors of various geopolymer/steel-slag interfacial systems were elucidated and compared. It is found that the Ca2SiO4, Ca2Fe2O5 and CaCO3 of steel slag aggregate show strong hydrophilicity, attracting water molecules to accumulated on its mineral surface and promoting the diffusion of Ca2+ and Na + at the interface. The interaction energy of geopolymer/steel-slag systems is mainly composed of electrostatic interaction energy. Thanks to the accumulation of water molecules on the mineral surface, the stronger hydrogen bond interaction occurs at the interface of the geopolymer/steel-slag system. The free metal cations from mineral surfaces and geopolymer binder respectively are coordinated with the accumulated water molecules to emerge hydrated ions, forming composite ionic clusters to stabilize the interfacial interaction. Mechanically, the interaction systems with C-A-S-H binder possess stronger interfacial tensile strength and shear strength. Steel slag with higher Ca2SiO4 content can effectively form strong interfacial bonding, lowering the risk of interfacial tensile failure, whereas steel slag containing more Ca2Fe2O5 can reduce occurrence possibility of shearing damage. CaCO3 formed by carbonization of steel slag, is conductive to strengthening the interfacial interaction with geopolymer binder.
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•MD simulation can reveal the interfacial behaviors of geopolymer/steel-slag.•The interfacial interaction of geopolymer/steel-slag is mainly composed of electrostatic interaction.•The water molecules at the interface produce hydrogen bond interaction.•The water molecules, Ca2+ and Na + migrate to the interface to form hydrated ions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•MD simulation can reveal the effect of moisture on interfacial behaviors of geopolymer-aggregate interaction;•Wetting characteristics of aggregate surfaces were elucidated and ...compared.•The interfacial mechanism of geopolymer-aggregate with the participation of moisture was explained.•Mechanical behaviors of geopolymer-water-aggregate interface were investigated using peeling and shearing simulation.
The interaction between geopolymer and aggregate largely determines the mechanical properties and durability of the geopolymer concrete. The effects of moisture on interfacial behavior of geopolymer-aggregate interaction are poorly understood, especially at molecular level. Herein, molecular dynamics (MD) simulation was employed to reveal the interactive behaviors of geopolymer-aggregate interfacial system with the participation of moisture. Full atomistic models adopted for MD simulations were constructed using the sodium aluminum silicate hydrate (N-ASH) gel model and the main chemical components of the aggregates, SiO2 and CaCO3. Then the wetting characteristics of aggregate surfaces, interfacial characteristics and mechanical behaviors of the geopolymer-aggregate interfacial systems containing interfacial moisture were elucidated and compared. It is found that the SiO2 surface is hydrophobic while the CaCO3 surface exhibits hydrophilic characteristics. Interfacial moisture participates in electrostatic interaction, H-bond interaction and coordination interaction in geopolymer-aggregate interface area. Appropriate interfacial water is beneficial to the interfacial interaction of geopolymer-aggregate system, but excessive water will increase the risk of interfacial failure. The interfacial moisture affects the diffusion behavior of water molecules and Na+ ions in geopolymer to the interfacial region, and the formation of H-bonds and coordination bonds at the interface. Mechanically, with the participation of interfacial moisture, the geopolymer-SiO2 interfacial system possesses stronger tensile strength, and a greater risk of shear failure than that of geopolymer-CaCO3. The above atomic-level findings may facilitate a better design and fabrication of geopolymer concrete in engineering.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The Gaussian particle probability hypothesis density filter (GPPHDF) needs conventional Monte-Carlo (MC) sampling in predict step and update step, which decreases the accuracy and real-time ...performance of the algorithm. This paper employs Quasi-Monte-Carlo (QMC) sampling to replace MC sampling, and QMC integration method is introduced to approximating the prediction and update distributions of target states. Hence a tracking algorithm based on the QMC method is proposed, which reduces the computational complexity and improves the accuracy and stability of the tracking algorithm.
The test of panel’s display effect is a key step in the panel production. Lighting inspection machines test the electrical, optical and surface information of Plasma Display Panels (PDPs). This ...machine is based on a PLC control system and a color analysis system. The PLC system controls a visual positioning system and links to Manufacturing Execution System (MES) and a panel conveyor. This paper considers the structure design and action workflow of the lighting inspection machine. Multi-layer network is built to connect with the whole production system. Optional operation modes are designed in control program and Man-machine interface is introduced to facilitate the operation.
