scholarly journals Road performance analysis of cement stabilized coal gangue mixture

2021 ◽  
Author(s):  
Zhenxia Li ◽  
Tengteng Guo ◽  
Yuan Zhao Chen ◽  
Xu Zhao ◽  
Yanyan Chen ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Optimal Allocation ◽  
Spontaneous Combustion ◽  
Base Material ◽  
Coal Gangue ◽  
Stone Materials ◽  
Road Performance ◽  
Dry Shrinkage

Abstract In order to solve the environmental pollution of coal gangue and the shortage of aggregate resources in road engineering, waste coal gangue is used as road base material instead of natural stone materials. Through physical, mechanical, chemical and activity tests of coal gangue aggregate, the optimal gradation composition of unconfined compressive strength was determined. Through unconfined compressive strength, indirect tensile strength, flexural tensile strength, freeze-thaw and dry shrinkage tests, the influence of cement content on road performance of cement stabilized coal gangue mixture was studied. By means of SEM, ICP AES, XRD and optical digital microscope, the difference between spontaneous combustion coal gangue and Unspontaneous combustion coal gangue was analyzed, the microstructure of cement stabilized coal gangue mixture was characterized, and the strength formation mechanism of mixture was explored. The results show that Spontaneous combustion coal gangue has higher activity than Unspontaneous combustion coal gangue.Based on the selected optimal allocation（BNS:SNS:SSC =71.26:9.41:18.8）,The mixture of 4% cement dosage can not only meet the requirement of early strength 4.16 MPa, but also show an efficient strength growth rate of 36.10%, showing the optimum mechanical properties. The total shrinkage coefficient of cement stabilized coal gangue mixture with 4% cement dosage is 1.12×10-2, which shows that the dry shrinkage resistance is the best. With the increase of time, hydration degree is gradually deepened, and gelled substance is more tightly bonded to aggregates. There is no obvious gap between aggregates, and the integrity of the mixture is enhanced, which can show better road performance. Ca (OH)2, a cement hydration product in cement stabilized coal gangue mixture, takes place pozzolana reaction with active SiO2 and Al2O3 in coal gangue to produce gismondine, which is beneficial to the global strength and the bond quality of the mixture.

scholarly journals Use of Factory-Waste Shingles and Cement Kiln Dust to Enhance the Performance of Soil Used in Road Works

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Aly Ahmed ◽  
Medhat Shehata ◽  
Said Easa
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Capillary Rise ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Fine Grained Soil ◽  
Stabilized Soil ◽  
Cement Manufacturing ◽  
Kiln Dust

An experimental work was conducted to study the use of factory-waste roof shingles to enhance the properties of fine-grained soil used in road works. Cement kiln dust (CKD), a cogenerated product of Portland cement manufacturing, was used as a stabilizing agent while the processed shingles were added to enhance the soil tensile strength. The effects of shingles on strength and stability were evaluated using the unconfined compressive strength, splitting tensile strength, and California Bearing Ratio (CBR) tests. The results showed that the use of CKD alone resulted in a considerable increase in the unconfined compressive strength but had a small effect on the tensile strength. The addition of shingles substantially improved the tensile strength of the stabilized soil. A significant reduction in the capillary rise and a slight decrease in the permeability were obtained as a result of shingle addition. An optimal shingle content of 10% is recommended to stabilize the soil.

Study on the Relationship between Soil-Cement Parameters and Unconfined Compressive Strength

2011 ◽  
Vol 255-260 ◽  
pp. 4012-4016
Author(s):  
Jun Qing Ma ◽  
You Xi Wang
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Shear Strength ◽  
Unconfined Compressive Strength ◽  
Deformation Modulus ◽  
Soil Cement ◽  
Strength And Deformation ◽  
Cement Soil ◽  
Relationship Of ◽  
The Relationship

This paper studies relationship between soil-cement parameters and unconfined compressive strength. The research in tensile strength and deformation modulus of soil-cement is an important basis for soil-cement failure mechanism and intensity theory. They also impact cracks, deformation and durability of cement-soil structure. Shear strength and deformation of soil-cement is important to the destruction analysis and finite element calculations. Therefore it needs to study on tensile strength, shear strength and deformation modulus of soil-cement. Based on previous experiments, the relationship of tensile strength, shear strength, deformation modulus and unconfined compressive strength of soil-cement are quantitatively studied.

scholarly journals Study on Mechanical Properties of PET Fiber-Reinforced Coal Gangue Fine Aggregate Concrete

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yanlin Huang ◽  
An Zhou
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Plain Concrete ◽  
Coal Gangue ◽  
Fine Aggregate ◽  
Replacement Rate ◽  
River Sand ◽  
Aggregate Concrete

In recent years, with the rapid development of the construction industry, the demand for natural river sand has become increasingly prominent. Development of alternatives to river sand has become an interesting direction for concrete research. In this paper, coal gangue was proposed to replace part of the river sand to produce coal gangue fine aggregate concrete, while waste polyethene terephthalate (PET) bottles were used as raw materials to make PET fibers to improve the mechanical properties of coal gangue fine aggregate concrete. There were two parts of the test conducted. In the first part, the compressive strength of the gangue fine aggregate concrete cube, splitting tensile strength, axial compressive strength, and static elastic modulus were studied when the substitution rate of coal gangue increased from 0% to 50%. Referring to the equation of the full stress-strain curve of plain concrete, the stress-strain constitutive equation of coal gangue fine aggregate concrete was analyzed and studied. By comparing with plain concrete, it was found that the coal gangue concrete with a replacement rate of 50% had higher compressive strength and tensile strength, but its brittleness was significantly greater than that of plain concrete in the later stage. In the second part, by studying the effect of different PET fiber content on the mechanical properties of coal gangue fine aggregate concrete with a replacement rate of 50%, it was found that when the addition of PET fiber was 0.1% and 0.3%, not only were compressive strength, splitting tensile strength, static elastic modulus, and flexural strength of the gangue fine aggregate concrete effectively improved but also the brittleness of concrete can be significantly reduced. The study found that after adding 0.3% PET fiber, the coal gangue fine aggregate concrete with a replacement rate of 50% has better mechanical properties and less brittleness.

Research on the Mechanical Performance of the Road Base Materials with Steel Slag Sand

2012 ◽  
Vol 174-177 ◽  
pp. 676-680
Author(s):  
Fang Xu ◽  
Ming Kai Zhou ◽  
Jian Ping Chen
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Mechanical Performance ◽  
Steel Slag ◽  
Base Material ◽  
Strength Performance ◽  
The Road ◽  
Road Base ◽  
Base Materials

The unconfined compressive strength is used to be the valuation index, the mechanical performance of three kinds of new road base material, which are fly ash stabilized steel slag sand (FA-SS for short), lime and fly ash stabilized steel slag sand (L-FA-SS for short), cement and fly ash stabilized steel slag sand(C-FA-SS for short), are studied in this paper. The results show that the unconfined compressive strength performance of FA-SS is similar to L-FA-SS, and it can meet the highest strength when the ratio of steel slag to fly ash is 1:1~2:1. When the ratio of fly ash to the steel slag is 10:90, it is good to use cement stabilizing. Comparing the new road base materials with the traditional road base material, the former has better strength performance and economy function advantage.

scholarly journals Evaluation for the Leaching of Cr from Coal Gangue Using Expansive Soils

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 478 ◽  
Author(s):  
Yan Zhang ◽  
Hassan Baaj ◽  
Rong Zhao
Keyword(s):  
Heavy Metal ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Building Materials ◽  
Negative Impact ◽  
Expansive Soil ◽  
Coal Gangue ◽  
Engineering Properties ◽  
Leaching Behavior ◽  
The Impact

Coal gangue can cause significant heavy metal pollution in mining areas, which would have a negative impact on the environment and human health. The objective of this research is to investigate the relationship between expansive soil amount and the leaching behavior of Chromium from coal gangue and the engineering properties of coal gangue used as building materials. The leaching behavior of Chromium from coal gangue was observed using atomic absorption spectrometry. A column leaching experiment was conducted to examine the impact of leaching time and heavy metal concentration. Furthermore, the unconfined compressive strength test was employed to evaluate the engineering properties of coal gangue with expansive soil. The results of the study demonstrate that pH of leachate solutions, leaching time, and expansive soil amounts in mixtures have important influence on Chromium concentration. The leachate solutions, which behave like alkaline, provide a positive environment for adsorbing Cr. Adding expansive soil can reduce leached concentrations of Chromium from coal gangue when compared to leachate of original coal gangue. It was found that 30% expansive soil was an improved solution because it delayed the cumulative concentration to reach the limitation line. Moreover, the unconfined compressive strength of coal gangue was boosted through adding expansive soil.

Laboratory Performance Evaluation of Cement-Stabilized Soil Base Mixtures

2000 ◽  
Vol 1721 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Louay N. Mohammad ◽  
Amar Raghavandra ◽  
Baoshan Huang
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Resilient Modulus ◽  
Flexible Pavements ◽  
Indirect Tensile Strength ◽  
Treated Soil ◽  
Stabilized Soil ◽  
Indirect Tensile ◽  
Soil Mixtures

In-place cement-stabilized soils have served as the primary base material for the majority of noninterstate flexible pavements in Louisiana for many years. These materials are economically and easily constructed and provide outstanding structural characteristics for flexible pavements. However, these cement-treated materials crack due to shrinkage, with the cracks reflecting from the base to the surface. A laboratory study examined the performance of four different cement-stabilized soil mixtures recently used in the construction of test lanes at the Louisiana Pavement Testing Facilities. Laboratory tests included the indirect tensile strength and strain, unconfined compressive strength, and indirect tensile resilient modulus tests. The four mixtures were ( a) in-place-mixed cement-treated soil with 10 percent cement, ( b) plant-mixed cement-treated soil with 10 percent cement, ( c) plant-mixed cement-treated soil with 4 percent cement, and ( d) plant-mixed cement-treated soil with 4 percent cement and fiber reinforcement. The results indicated that there was no significant difference in performance between the plant-mixed and in-place-mixed cement-treated soil mixtures. The inclusion of fiber to the cement-treated soil mixture significantly increased the indirect tensile strain and the toughness index. Increases in compaction effort maintained or significantly increased the indirect tensile strength and unconfined compressive strength. Increases in curing period maintained or significantly increased indirect tensile and unconfined compressive strength as well as the resilient modulus of the mixtures.

Prediction of Triaxial Compressive Strength of Geomaterials Based on a Failure Criterion

2012 ◽  
Author(s):  
Hossein Bineshian ◽  
Zahra Bineshian
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Strength Criterion ◽  
Nonlinear Regression Model ◽  
Popular Method ◽  
Loading Direction ◽  
Triaxial Compressive Strength ◽  
Wide Range ◽  
Two Parameters

Ramamurthy et al strength criterion is applicable only for compression. Tensile strength and unconfined compressive strength cannot be calculated by the criterion. Ramamurthy et al criterion contains two parameters as inherent constants of geomaterials that are known as B and α. A popular method to predict the strength by a certain criterion is using the proposed values for the criterion’s parameters, authors in this paper suggested suitable practical values for the parameters and a precise equation for B for a wide range of geomaterials. Also especial consideration has been pertained for soft geomaterials to calculate the parameters for different conditions of weak planes and loading direction. Moreover authors have presented linear conversion and nonlinear regression model for Ramamurthy et al criterion to extract the mathematical coefficients and the strength criterion’s parameters. Using these parameters for seabed geomaterials will present a fast, useful and credible prediction for the compressive strength by this modified strength criterion.

Statistical Models to Predict Tensile Strength from Unconfined Compressive Strength: Case Study from Southern Iraq

2021 ◽  
Author(s):  
Husam Hasan Alkinani ◽  
Abo Taleb Tuama Al-Hameedi ◽  
Shari Dunn-Norman ◽  
Mustafa Adil Al-Alwani
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Least Squares ◽  
Unconfined Compressive Strength ◽  
Mean Squared Error ◽  
Time Factors ◽  
Absolute Error ◽  
Tensile Failure ◽  
Least Squares Regression ◽  
Southern Iraq

Abstract Tensile strength (To) is an important parameter for creating geomechanical models, especially when tensile failure is the failure of interest. The most common way to estimate the tensile strength is by utilizing Brazilian tests. However, due to material limitation, cost, or time, To is sometimes assumed or estimated empirically. In this work, laboratory test data of To and Unconfined Compressive Strength (UCS) conducted for three zones in southern Iraq (Zubair sandstone, Zubair shale, and Nahr Umr shale) were utilized to create three regression models to estimate To from UCS. The reason for selecting UCS as the independent parameter is that static UCS, in most cases, has to be estimated from laboratory tests to create robust geomechanical models. In other words, UCS will be given the preference over Towhen there is the material limitation, cost, or time involved. The data of each zone were divided into training (80%) and testing (20%) to ensure the models can generalize for new data and avoid overfitting. Multiple least squares fits were tested, and linear least squares regression was selected since it provided the highest R2 and the lowest error. The models yielded training R2 of 0.983, 0.988, and 0.965 while the testing R2 were 0.978, 0.990, and 0.993 for Zubair sandstone, Zubair shale, and Nahr Umr shale, respectively. The errors were assessed using root mean squared error (RMSE) and mean absolute error (MAE), and they both have shown an acceptable margin of error for all three models. In short, the created three models showed the ability to estimate To from UCS when material limitation, cost, or time factors are involved or when executing a Brazilian test is not applicable. The proposed models can contribute to robust geomechanical models as well as minimizing cost, time, and material usage.

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