Miniature cone tip resistance of sand with fly ash using triaxial setup

2009 ◽  
Vol 46 (2) ◽  
pp. 231-240 ◽  
Author(s):  
Jyant Kumar ◽  
K. V.S.B. Raju
Keyword(s):  
Fly Ash ◽  
Relative Density ◽  
Friction Angle ◽  
Soil Mass ◽  
Ash Content ◽  
Sand Fly ◽  
Cohesionless Soils ◽  
Overburden Pressure ◽  
Cone Tip Resistance ◽  
Tip Resistance

In a continuation of the authors’ recent work, the ultimate tip resistance of a miniature cone using triaxial equipment was determined for samples of dry sand mixed with dry fly ash. The effect of (i) the proportion of fly ash, (ii) the relative density of samples, and (iii) the vertical overburden pressure was examined. It was noted that an addition of fly ash in sand for the same range of relative density leads to a significant reduction in the ultimate tip resistance of the cone (qcu). This occurs due to a decrease in the friction angle (ϕ) of the sample with an increase in the fly ash content for a given relative density. For ϕ greater than about 30°, two widely used correlation curves from published literature, providing the relationships between qcu and ϕ for cohesionless soils, were found to provide satisfactory predictions, even for sand – fly ash mixtures. As was expected, the values of qcu increase continuously with an increase in the relative density of the soil mass and the vertical effective (overburden) stress on the sample.

Evaluation on Features of Soft Foundation Engineering and Bearing Layer of Pile in Jiaxing City

2011 ◽  
Vol 90-93 ◽  
pp. 217-221
Author(s):  
Jin Long Zhou ◽  
Qiao Li ◽  
Wei Zhong Cai
Keyword(s):  
Soil Mass ◽  
Shallow Foundation ◽  
Silty Clay ◽  
Foundation Engineering ◽  
Foundation Soil ◽  
Cone Tip Resistance ◽  
Soft Foundation ◽  
Tip Resistance ◽  
Bearing Layer

Through the investigation into composition of major shallow foundation soil mass and the correlation of mechanical indicators in this study, the regression equation of mechanical indicators of the features of local foundation soil mass and the data of in situ testing was obtained. Based on massive quantities of exploration materials, this study analyzed engineering features, distribution status, and the feasibility of silty clay to be used as the bearing layer of the pile in Layer ④2 . The analytical results showed that the silty clay with the uniform depth of over 3.5m and the cone tip resistance in static sounding of over 400MPa could be used as bearing layer of the pile. This study could provide the reference for the accurate understanding of the engineering features of soil mass, and the design and evaluation of foundation in Jiaxing City.

scholarly journals Improvement of the Salinized Soil Properties of Fly Ash by Freeze-Thaw Cycles: An Impact Test Study

2021 ◽  
Vol 13 (5) ◽  
pp. 2908
Author(s):  
Zhuo Cheng ◽  
Gaohang Cui ◽  
Zheng Yang ◽  
Haohang Gang ◽  
Zening Gao ◽  
...  
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Internal Friction ◽  
Unconfined Compressive Strength ◽  
Saline Soil ◽  
Friction Angle ◽  
Ash Content ◽  
Internal Friction Angle ◽  
Freeze Thaw ◽  
Salinized Soil

To explore the mechanism of the microstructural change in salinized soil under freeze-thaw cycles and the strength characteristics of subgrade salinized soil improved by fly ash, an unconfined compressive test, a triaxial shear test, and a scanning electron microscopy test were carried out using salinized soil samples with different fly ash contents along the Suihua to Daqing expressway in China. The results showed that after several freeze-thaw cycles, the unconfined compressive strength, triaxial shear strength, cohesion, and internal friction angle of saline soil showed a decreasing trend. With an increase in the fly ash content, the internal friction angle, cohesion, unconfined compressive strength, and shear strength of the improved saline soil first increased and then decreased. When the fly ash content was 15%, the mechanical indexes, such as cohesion and the internal friction angle, reached the maximum value. Microscopic test results showed that the freeze-thaw cycle will lead to an increase in the proportion of pores and cracks, an increase in the average pore size, and a loosening of the soil structure. The addition of fly ash can fill the soil pores, improve the microstructure of the soil, increase the cohesive force of the soil particles, and improve the overall strength of the soil. Fly ash (15%) can be added to subgrade soil in the process of subgrade construction in the Suihua-Daqing expressway area to improve the shear strength and the resistance to freezing and thawing cycles. These research results are conducive to promoting the comprehensive utilization of fly ash, improving the utilization rate of resources, and promoting sustainable development, thus providing a reference for the design and construction of saline soil roadbed engineering in seasonal frozen areas and the development and construction of saline land belts in seasonal and winter areas.

scholarly journals Experimental investigations for assessing the influence of fly ash on the flow through porous media in Darcy regime

2021 ◽  
Vol 83 (5) ◽  
pp. 1028-1038
Author(s):  
Abhishish Chandel ◽  
Vijay Shankar ◽  
M. A. Alam
Keyword(s):  
Porous Media ◽  
Fly Ash ◽  
Hydraulic Conductivity ◽  
Ash Content ◽  
Sand Fly ◽  
Unit Weight ◽  
Experimental Investigations ◽  
Dry Density ◽  
Empirical Equations ◽  
River Sand

Abstract Hydraulic conductivity plays a vital role in the studies encompassing explorations on flow and porous media. The study investigates the compaction characteristics of a river sand (Beas, Sutlej, and Ghaggar rivers) and fly ash mix in different proportions and evaluates four empirical equations for estimating hydraulic conductivity. Experiments show that an increase in the fly ash content results in a decrease in the maximum dry density (MDD) and an increase in the corresponding optimum moisture content (OMC) of sand–fly ash samples. MDD at optimum fly ash content was achieved at low water content, which resulted in less dry unit weight than that of typical conventional fill. In Beas, Sutlej, and Ghaggar sands the optimum fly ash content up to which the hydraulic conductivity value reduced uniformly was found to be 30, 45, and 40%, respectively. Any further increase in the fly ash content results in a negligible decrease in hydraulic conductivity value. The observed hydraulic conductivity of sand–fly ash mix lies in the range of silts, which emboldens the use of sand–fly ash mix as embankment material. Further, the evaluation of empirical equations considered in the study substantiates the efficacy of the Terzaghi equation in estimating the hydraulic conductivity of river sand-fly ash mix.

scholarly journals Study on Rheological and Mechanical Properties of Aeolian Sand-Fly Ash-Based Filling Slurry

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1266
Author(s):  
Xiaoping Shao ◽  
Long Wang ◽  
Xin Li ◽  
Zhiyu Fang ◽  
Bingchao Zhao ◽  
...  
Keyword(s):  
Fly Ash ◽  
Rheological Properties ◽  
Economic Benefits ◽  
Ash Content ◽  
Sand Fly ◽  
Strength Development ◽  
Hydration Reaction ◽  
Aeolian Sand ◽  
Delayed Reaction ◽  
Uniaxial Test

Backfill mining is the most environmentally friendly mining method at present, which can effectively control the surface subsidence, improve the recovery rate, and has good social and economic benefits. The purpose of this study is to solve the environmental problems caused by solid waste, combined with the rich geographical advantages of aeolian sand in the Yushenfu mining area of China. The rheological properties of the aeolian sand-fly ash-based filling slurry with different fly ash content are studied by experiments, and the strength development law of the filling body under different age and fly ash content are studied from the macroscopic and microscopic points of view. The rheological experiments showed that the increase of the amount of fly ash has a significant effect on the thixotropy, plastic viscosity, and yield stress of the filling slurry. Additionally, rheological properties of aeolian sand-fly ash-based filling slurry conform to the Bingham model. With the increase of the amount of fly ash, the performance of the filling slurry has been significantly improved. Uniaxial test and scanning electron microscope observation showed that the influence of fly ash on the strength of the filling body was mainly reflected in the late stage of maintenance, but was not obvious in the middle stage. Fly ash particles mainly bear the role of “water reduction” and a physical filling effect, which makes the filling slurry thicker and the internal structure more closely spaced. The volcanic ash reaction of fly ash is lagging behind the hydration reaction of cement; the secondary product of the delayed reaction is filled in the pores of cement hydrates, which can greatly reduce the porosity of the backfill body and increase the later strength of the backfill body. It provides a guarantee for the safe replacement of coal pillars in the working face.

scholarly journals Study on Mechanical and Ecological Properties of Fly Ash Substrate for Ecological Slope Protection

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Juan Wan ◽  
Jun Zhu ◽  
Henglin Xiao ◽  
Qiang Ma
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Moisture Content ◽  
Friction Angle ◽  
Ash Content ◽  
Class V ◽  
Ecological Requirements ◽  
Msw Incineration ◽  
Standard Limit ◽  
Root Content

In order to realize the resource utilization of fly ash, a kind of ecological slope protection substrate was prepared by mixing fly ash produced by MSW incineration into slope protection soil. Through the direct shear test and a leaching experiment on ion pollutants, the influence that shear strength of the substrate changed with root content, ash content, and moisture content and the ecological effects of leach liquor were investigated. The results showed the following: (1) When the optimum moisture content is about 24.9%, the shear strength of the substrate is the maximum. (2) Fly ash can improve the shear strength of the soil, which can reach 1.67 times as much as that of plain soil, and the optimum content of fly ash is 5%–6.7%. (3) The root system can increase the cohesion and internal friction angle of the substrate soil but mainly increases the cohesion of the substrate soil. (4) Plants grow taller in ash-mixed soil than in plain soil. (5) When the fly ash content is 20%, the ion concentrations of Cl, Cu, and Zn are the highest: 220.7, 0.153, and 1.526 mg/L, respectively. All of them are lower than the standard limit of class V water and gradually decrease with time. Therefore, the leaching liquid will not cause environmental pollution and meet the ecological requirements.

scholarly journals Quantitative Analysis of the Relationship Between Shear Strength and Fractal Dimension of Solidified Dredger Fill with Different Fly Ash Content Under Monotonic Shear

2018 ◽  
Vol 25 (s2) ◽  
pp. 132-138 ◽  
Author(s):  
Yang Shuai ◽  
Liu Wenbai ◽  
Liu Hongwei
Keyword(s):  
Shear Strength ◽  
Fractal Dimension ◽  
Fly Ash ◽  
Particle Surface ◽  
Fractal Dimensions ◽  
Friction Angle ◽  
Ash Content ◽  
Strength Index ◽  
Dredger Fill ◽  
The Relationship

Abstract The dredger fill of Shanghai Hengsha Island Dongtan is solidified by curing agents with different fly ash content, and the shear strength index of solidified dredger fill is measured by the direct shear test. The microscopic images of solidified dredger fill are obtained by using SEM. The microscopic images are processed and analyzed by using IPP, and the fractal dimension including particle size fractal dimension Dps, aperture fractal dimension Dbs and particle surface fractal dimension Dpr is calculated by fractal theory. The quantitative analysis of the relationship between shear strength index and fractal dimension of solidified dredger fill is done. The research results show that the internal friction angle and the cohesion are closely related to the fly ash content λ and the curing period T, and the addition of fly ash can improve the effect of curing agent; There is no obvious linear relationship between the internal friction angle and the three fractal dimensions; The smaller particle surface fractal dimension Dpr and particle size fractal dimension Dps, the larger aperture fractal dimension Dbs, the greater the cohesion, and the cohesion has a good linear relationship with three fractal dimensions, and the correlation coefficient R2 is above 0.91.

The Influence of the Ash Addition from Thermal Power Plant on the Mechanical, Thermal and Dielectric Characteristics of Mortars

2018 ◽  
Vol 69 (8) ◽  
pp. 2040-2044
Author(s):  
Georgeta Velciu ◽  
Virgil Marinescu ◽  
Adriana Moanta ◽  
Ladislau Radermacher ◽  
Adriana Mariana Bors
Keyword(s):  
Thermal Conductivity ◽  
Fly Ash ◽  
Power Plant ◽  
Cement Mortar ◽  
Thermal Power ◽  
Total Content ◽  
Ash Content ◽  
Dielectric Losses ◽  
Dielectric Characteristics ◽  
Cement Mortars

The influence of fly ash adittion (90 % fraction [ 100 mm) on the cement mortar characteristics was studied. The XRD, XRF, SEM and FTIR determinations indicated that fly ash used has a hollow microstructure of microsphere and cenosphere whose total content in SiO2, Al2O3 and Fe2O3 is 88.63 % and that of CaO and MgO of 8.55 %. The mechanical, thermal and dielectric determinations made on mortar samples with content of fly ash in the 0-40 % range have highlighted fact that the mechanical strength of cement mortars is maximal at 20 %, the increase in fly ash content leads to a decrease in relative density and thermal conductivity as well as and to increased dielectric losses tgd.

Assessment of Hydration Degree of Cement in the Fly Ash-Cement Pastes Based on the Calcium Hydroxide Content

2014 ◽  
Vol 875-877 ◽  
pp. 177-182 ◽  
Author(s):  
Xiang Li ◽  
Hua Quan Yang ◽  
Ming Xia Li
Keyword(s):  
Fly Ash ◽  
Calcium Hydroxide ◽  
Cement Hydration ◽  
Ash Content ◽  
Content Increase ◽  
Hydration Degree ◽  
Equilibrium Calculation ◽  
Cement Pastes ◽  
Cement Ratio ◽  
Water Cement Ratio

The hydration degree of fly ash and the calcium hydroxide (CH) content were measured. Combined with the equilibrium calculation of cement hydration, a new method for assessment of the hydration degree of cement in the fly ash-cement (FC) pastes based on the CH content was developed. The results reveal that as the fly ash content increase, the hydration degree of fly ash and the CH content decrease gradually; at the same time, the hydration degree of cement increase. The hydration degree of cement in the FC pastes containing a high content of fly ash (more than 35%) at 360 days is as high as 80%, even some of which hydrates nearly completely. The effect of water-cement ratio to the hydration degree of cement in the FC pastes is far less distinct than that of the content of fly ash.

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