scholarly journals Experimental Research on Foamed Mixture Lightweight Soil Mixed with Fly-Ash and Quicklime as Backfill Material behind Abutments of Expressway Bridge

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Xin Liu ◽  
Ke Sheng ◽  
Zhi-long Li ◽  
Liang-qin Gan ◽  
Hao Shan ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Narrow Range ◽  
Cement Content ◽  
Orthogonal Experiment ◽  
Construction Techniques ◽  
Key Points ◽  
Experiment Method ◽  
Orthogonal Experiment Method

To promote the utilization of fly-ash, based on the orthogonal experiment method, wet density and unconfined compressive strength of Foamed Mixture Lightweight Soil mixed with fly-ash and quicklime (FMLSF) are studied. It is shown that the wet density and unconfined compressive strength of FMLSF increase with the increase of cement content, while decreasing with the increase of foam content. With the mixing content of fly-ash increase, the wet density and unconfined compressive strength of FMLSF increase firstly and then decrease. Scanning Electron Microscope (SEM) tests show that ball effect or microaggregate effect of fly-ash improves the wet density and unconfined compressive strength of FMLSF. With the mixing content of quicklime increase, the wet density and unconfined compressive strength of FMLSF increase firstly within a narrow range and then decrease. In addition, the primary and secondary influence order on wet density and 28-day compressive strength of FMLSF are obtained, as well as the optimal mixture combination. Finally, based on two abutments in China, behind which they are filled with FMLSF and Foamed Mixture Lightweight Soil (FMLS), the construction techniques and key points of quality control behind abutment are compared and discussed in detail, and the feasibility of utilization fly-ash as FMLSF is verified by the experimental results.

scholarly journals Mechanical Properties of Furnace Slag and Coal Gangue Mixtures Stabilized by Cement and Fly Ash

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7103
Author(s):  
Hongbo Li ◽  
Hubiao Zhang ◽  
Pengfei Yan ◽  
Changyu Yan ◽  
Yufei Tong
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Peak Stress ◽  
Coal Gangue ◽  
Replacement Rate ◽  
Splitting Strength ◽  
The Relationship

The mechanical properties and strength formation mechanism of cement–fly-ash-stabilized slag–coal gangue mixture were examined using an unconfined compressive strength test, splitting strength test, triaxial test, and scanning electron microscopy to solve the limitations of land occupation and environmental pollution that is caused by fly ash from the Xixia District thermal power plant in Yinchuan, slag from the Ningdong slag yard, and washed coal gangue. Its performance as a pavement base mixture on the road was investigated. The results demonstrated that as the slag replacement rate increased, the maximum water content increased while the maximum dry density decreased. The addition of slag reduced the unconfined compressive strength and splitting strength of the specimens; furthermore, the higher the slag substitution rate, the lower the unconfined compressive strength and splitting strength of the specimens. As the cement content increased, the specimen’s unconfined compressive strength increased. Based on the principle of considering the mechanical properties and economic concerns, the slag replacement rate in the actual construction should be ~50% and should not exceed 75%. Based on the relationship between the compressive strength and splitting strength of ordinary concrete, the relationship model between the unconfined compressive strength and splitting strength of cement–fly-ash-stabilized slag–coal gangue was established. The failure mode, stress–strain curve, peak stress, and failure criterion of these specimens were analyzed based on the triaxial test results, and the relationship formulas between the slag substitution rate, cement content, peak stress, and confining pressure were fitted. As per the SEM results, the mixture’s hydration products primarily included amorphous colloidal C-S-H, needle rod ettringite AFt, unhydrated cement clinker particles, and fly ash particles. The analysis of the mixture’s strength formation mechanism showed that the mixture’s strength was the comprehensive embodiment of all factors, such as the microaggregate effect, secondary hydration reaction, and material characteristics.

Study on Technological Conditions of Red Mud-Coal Gangue Lightweight Pottery Sand

2014 ◽  
Vol 599 ◽  
pp. 350-354
Author(s):  
Dong Mei Zhang ◽  
Jian Hua Yan ◽  
Su Ping Cui ◽  
Ren Hai Yang ◽  
Bao Xue Pang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Single Particle ◽  
Red Mud ◽  
Orthogonal Experiment ◽  
Coal Gangue ◽  
Experiment Method ◽  
Orthogonal Experiment Method ◽  
Softening Coefficient ◽  
Expansion Temperature

The technological conditions for preparation of red mud-coal gangue lightweight pottery sand were studied. The formulation of the lightweight pottery sand was determined by comparing the sintering images. The results indicated that as to the mixture of red mud and coal gangue, the expansion temperature of mixture decreased with increasing the content of red mud. The composition of 30% red mud and 70% coal gangue was determined to have the best expanding performance in this study and selected. The optimal technological conditions of lightweight pottery sand was systematically studied through orthogonal experiment method and accordingly the lightweight pottery sand with bulk density of 617.89kg/m3, water absorption of 0.14%, the single particle compressive strength of 2.95MPa, the softening coefficient of 0.98 was successfully prepared with the selected composition after preheated at 550°C for 20 min and then sintered at 1300°C for 20min.

Study on Preparation and Mechanical Properties of Magnesium Phosphate Cement

2014 ◽  
Vol 1049-1050 ◽  
pp. 416-421
Author(s):  
Run Qing Liu ◽  
Ding Qiang Chen ◽  
Tian Bo Hou
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Orthogonal Experiment ◽  
Setting Time ◽  
Comprehensive Analysis ◽  
Magnesium Phosphate ◽  
Adhesive Properties ◽  
Rapid Repair ◽  
Experiment Method ◽  
Orthogonal Experiment Method

The orthogonal experiment method is utilized in this paper to get a comprehensive analysis of the compressive strength of magnesium phosphate cement (MPC) to prepare the cement with the best performance. What’s more, a further study is conducted on the compressive strength of paste and the compressive strength and the flexural strength of mortar, and the last is the adhesive properties. The results showed that the optimal ratio was obtained; the setting time of the optimum mix ratio of cement is 13min, which meets the requirements of rapid repair; the development of the strength of the paste and mortar all have the characteristics of early strength and fast hardening. Generally, the strength at 7d can reach the 90% of the strength at 28d, and the compressive strength of the paste at 28d can reach to 79.8MPa. The compressive strength and flexural strength of mortar at 28d are 53.2MPa and 11.3MPa, respectively.

scholarly journals Characterization and Comparison Research on Composite of Alluvial Clayey Soil Modified with Fine Aggregates of Construction Waste and Fly Ash

2021 ◽  
Vol 28 (1) ◽  
pp. 83-95
Author(s):  
Qu Jili ◽  
Wang Junfeng ◽  
Batugin Andrian ◽  
Zhu Hao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Clayey Soil ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Construction Waste ◽  
Comparison Research ◽  
Fine Aggregates ◽  
Optimum Water Content

Abstract Fine aggregates of construction waste and fly ash were selected as additives to modify the characteristics of Shanghai clayey soil as a composite. The laboratory tests on consistency index, maximum dry density, and unconfined compressive strength were carried out mainly for the purpose of comparing the modifying effect on the composite from fine aggregates of construction waste with that from fly ash. It is mainly concluded from test results that the liquid and plastic limit of the composites increase with the content of two additives. But their maximum dry density all decreases with the additive content. However, fine aggregates of construction waste can increase the optimum water content of the composites, while fly ash on the contrary. Finally, although the two additive all can increase the unconfined compressive strength of composites, fly ash has better effect. The current conclusions are also compared with previous studies, which indicates that the current research results are not completely the same as those from other researchers.

scholarly journals Investigation on cement-improved phyllite based on the vertical vibration compaction method

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247599
Author(s):  
Yingjun Jiang ◽  
Jiangtao Fan ◽  
Yong Yi ◽  
Tian Tian ◽  
Kejia Yuan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Static Pressure ◽  
Cement Content ◽  
Vertical Vibration ◽  
Pressure Method ◽  
Vibration Compaction ◽  
Modulus Of Resilience ◽  
Compaction Method

The vertical vibration compaction method (VVCM), heavy compaction method and static pressure method were used to form phyllite specimens with different degrees of weathering. The influence of cement content, compactness, and compaction method on the mechanical properties of phyllite was studied. The mechanical properties of phyllite was evaluated in terms of unconfined compressive strength (Rc) and modulus of resilience (Ec). Further, test roads were paved along an expressway in China to demonstrate the feasibility of the highly weathered phyllite improvement technology. Results show that unweathered phyllite can be used as subgrade filler. In spite of increasing compactness, phyllite with a higher degree of weathering cannot meet the requirements for subgrade filler. With increasing cement content, Rc and Ec of the improved phyllite increases linearly. Rc and Ec increase by at least 15% and 17%, respectively, for every 1% increase in cement content and by at least 10% and 6%, respectively, for every 1% increase in compactness. The higher the degree of weathering of phyllite, the greater the degree of improvement of its mechanical properties.

Natural Ventilation Design and Optimization of Large-Scale Industrial Workshop

2014 ◽  
Vol 1065-1069 ◽  
pp. 2137-2140
Author(s):  
Xiao Hu Yang ◽  
Yan Long ◽  
Ling Zhao Meng ◽  
Yu Hui Jin
Keyword(s):  
Large Scale ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Orthogonal Experiment ◽  
Structure Design ◽  
Iron And Steel ◽  
Design And Optimization ◽  
Experiment Method ◽  
Orthogonal Experiment Method ◽  
Computational Fluid Dynamics Cfd

In this paper, we used orthogonal experiment method and Computational Fluid Dynamics (CFD) technology to simulate the thermal environment of the iron and steel workshop. By comparing and analyzing the temperature distribution and air flow of workshops with different window structures, we obtained an optimization of natural ventilation design for industrial workshop. The research results can be used for the structure design or reformation of industrial workshops as reference.

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