Laboratory Study of Engineering Properties of Flowable Backfill Material

2014 ◽  
Vol 955-959 ◽  
pp. 2809-2812
Author(s):  
Zhang Hong ◽  
Guo Chao ◽  
Li Liang ◽  
Zhi Qiang Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Water Content ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Engineering Properties ◽  
Cleavage Strength ◽  
The Common ◽  
Common Problems ◽  
Content Range

Aimed at the common problems of small backfill space, hard to backfill, difficult to guarantee compaction quality in engineering, development law of fluidity and mechanical properties (unconfined compressive strength and cleavage strength) is analyzed by changing mix ratio of cement, fly ash and water. Fluidity is mainly controlled by water content. Range of fluidity is significantly different when water content is around 60％.Considering the effect of economy and strength, 4% cement content will be recommended.

scholarly journals Mechanical Properties of Sandy Soil Improved with Cement and Nanosilica

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Asskar Janalizadeh Choobbasti ◽  
Ali Vafaei ◽  
Saman Soleimani Kutanaei
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Sandy Soil ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Cylindrical Specimen ◽  
Engineering Properties ◽  
Nano Silica ◽  
Cement Based Materials ◽  
Nanosilica Particles

AbstractIn the literature, studies show that nanosilica particles and artificial pozzolans possessing can improve structural properties of cement-based materials. This paper studies the effect of cement and nanosilica on the engineering properties (compaction, unconfined compressive strength) of sand. Three different cement ratios (5, 9, and 14% by weight of dry sand) were mixed with four different nano silica ratios (0, 5, 10, and 15% by weight of cement), and then compacted into a cylindrical specimen. The results of the study presented that the addition of the cement and nanosilica improves the engineering properties of sands. The increase of maximum dry unitweight of sand was noted with the increase in the cement content. The presence of nanosilica in optimal percentages can significantly improve the mechanical properties of cement sand.

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.

Laboratory Experimental Research on Mix Ratio Test of Cement Soil

2013 ◽  
Vol 438-439 ◽  
pp. 197-201
Author(s):  
Xian Hua Yao ◽  
Peng Li ◽  
Jun Feng Guan
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Ratio Test ◽  
Curing Time ◽  
Curing Conditions ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Cement Soil

Based on the generalization and analysis of laboratory experimental results on mix ratio, the effects of various factors such as cement content, water-cement ratio, curing time, curing conditions and types of cement on the mechanical properties of unconfined compressive strength of cement soil are presented. Results show that the unconfined compressive strength of cement soil increases with the growing curing time, and it is greatly affected by the cement content, water-cement ratio, cement types and curing time, while the effect of curing conditions is weak with a cement content of more than 10%. Moreover, the stress-strain of the cement soil responds with the cement content and curing time, increasing curing time and cement content makes the cement soil to be harder and brittle, and leads to a larger Young's modulus.

Research about the Effect of Polypropylene Fiber on Mechanical Properties of Curing Sludge

2011 ◽  
Vol 250-253 ◽  
pp. 788-794
Author(s):  
Shu Lin Zhan ◽  
Shu Sen Gao ◽  
Jun Ying Lai
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Shear Strength ◽  
Water Content ◽  
Unconfined Compressive Strength ◽  
Polypropylene Fiber ◽  
Physical And Mechanical Properties ◽  
Curing Time ◽  
Strength Tests ◽  
Different Content

In order to study the influence of modified polypropylene (PP) fiber on the physical and mechanical properties of curing sludge, the same amount of cement and different content of polypropylene fiber were mixed into the sludge. Unconfined compressive strength tests, water content tests and shear strength tests were carried out on different specimens with different curing time. The results show that the sludge curing effect is markedly improved by the addition of the polypropylene fiber. As to the curing sludge with the same curing time, when the content of the polypropylene fiber increases, the unconfined compressive strength and the cohesive strength greatly increase, and the internal frictional angle decreases.

Characterization of a cemented sand with the pulse-velocity method

2006 ◽  
Vol 43 (3) ◽  
pp. 294-309 ◽  
Author(s):  
Zahid Khan ◽  
Anwar Majid ◽  
Giovanni Cascante ◽  
D Jean Hutchinson ◽  
Parsa Pezeshkpour
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Wave Velocity ◽  
Unconfined Compressive Strength ◽  
Void Ratio ◽  
Cement Content ◽  
Pulse Velocity ◽  
Initial Water Content ◽  
Strain Property ◽  
Cemented Sand

The effect of variation in cement content, initial water content, void ratio, and curing time on wave velocity (low-strain property) and unconfined compressive strength (large-strain property) of a cemented sand is examined in this paper. The measured pulse velocity is compared with predictions made using empirical and analytical models, which are mostly based on the published results of resonant column tests. All specimens are made by mixing silica sand and gypsum cement (2.5–20% by weight) and tested under atmospheric pressure. The wave velocity reaches a maximum at optimum water content, and it is mostly affected by the number of cemented contacts; whereas compressive strength is governed not only by the number of contacts but also by the strength of contacts. Experimental relationships are developed for wave velocity and unconfined compressive strength as functions of cement content and void ratio. Available empirical models underpredict the wave velocity (60% on average), likely because of the effect of microfractures induced by confinement during the testing. Wave velocity is found to be a good indicator of cement content and unconfined compressive strength for the conditions of this study.Key words: wave velocity, low-strain stiffness, cemented sands, elastic moduli, unconfined compressive strength.

Effect of Fly Ash Content on Mechanical Properties of Cement-Fly Ash Stabilized Crushed Stones

2014 ◽  
Vol 548-549 ◽  
pp. 228-232 ◽  
Author(s):  
Xiao Chen ◽  
Ji Wei Liu ◽  
Ming Kai Zhou
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Crack Resistance ◽  
Unconfined Compressive Strength ◽  
Resilient Modulus ◽  
Ash Content ◽  
Mechanical Parameters ◽  
Cleavage Strength ◽  
The Impact

To improve the impact of fly ash on the properties of cement-fly ash stabilized crushed stone, and promote it popularize and apply better. This paper investigated the effect of fly ash content on unconfined compressive strength, cleavage strength and resilient modulus of cement-fly ash stabilized crushed stones, and those relationships between mechanical parameters. The results showed that with increasing of the fly ash content, the unconfined compressive strength and cleavage strength increased at first, then decreased, the resilient modulus decreased, and The brittleness index increased. We can conclude that the optimal fly ash content is between 10% and 15%, and increment of fly ash content can improve its crack-resistance.

Effect of Fly Ash Content on Mechanical Properties of Cement-Fly Ash Stabilized Crushed Stones

2010 ◽  
Vol 168-170 ◽  
pp. 1881-1885
Author(s):  
Xiao Chen ◽  
Ming Kai Zhou ◽  
Jia Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Crack Resistance ◽  
Unconfined Compressive Strength ◽  
Resilient Modulus ◽  
Ash Content ◽  
Brittleness Index ◽  
Mechanical Parameters ◽  
Cleavage Strength

This paper investigates the effect of fly ash content on unconfined compressive strength, cleavage strength and resilient modulus of cement-fly ash stabilized crushed stones. The relationships between mechanical parameters were also studied. The results show that with fly ash content increasing, the unconfined compressive strength and cleavage strength were increasing firstly but decreased then, and the resilient modulus were decreasing. The brittleness index was increased by the increment of fly ash content. It can be concluded that the optimal fly ash content in cement-fly ash stabilized crushed stones is between 10% and 15%, and increment of fly ash content can improve its crack-resistance.

scholarly journals Mechanical Properties and Microstructure of Fibre-Reinforced Clay Blended with By-Product Cementitious Materials

Geosciences ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 241 ◽  
Author(s):  
Samuel J. Abbey ◽  
Eyo U. Eyo ◽  
Jonathan Oti ◽  
Samuel Y. Amakye ◽  
Samson Ngambi
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Glass Fibre ◽  
Unconfined Compressive Strength ◽  
Linear Expansion ◽  
Cement Content ◽  
Soil Reinforcement ◽  
Clayey Soils ◽  
Wide Range ◽  
Reinforced Cement

Clayey soils endure adverse changes in strength and volume due to seasonal changes in moisture content and temperature. It has been well recognised that high cement content has been successfully employed in improving the mechanical properties of clayey soils for geotechnical infrastructural purposes. However, the environmental setbacks regarding the use of high cement content in soil reinforcement have necessitated the need for a greener soil reinforcement technique by incorporating industrial by-product materials and synthetic fibres with a reduced amount of cement content in soil-cement mixtures. Therefore, this study presents an experimental study to investigate the mechanical performance of polypropylene and glass fibre-reinforced cement-clay mixtures blended with ground granulated blast slag (GGBS), lime and micro silica for different mix compositions and curing conditions. The unconfined compressive strength, linear expansion and microstructural analysis of the reinforced soils have been studied. The results show that an increase in polypropylene and glass fibre contents caused an increase in unconfined compressive strength but brought on the reduction of linear expansion of the investigated clay from 7.92% to 0.2% at fibre content up to 0.8% for cement-clay mixture reinforced with 5% Portland cement (PC). The use of 0.4–0.8% polypropylene and glass fibre contents in reinforcing cement-clay mixture at 5% cement content causes an increase in unconfined compressive strength (UCS) values above the minimum UCS target value according to American Society for Testing and Materials (ASTM) 4609 after 7 and 14 days curing at 20 °C to 50 °C temperature. Therefore, this new clean production of fibre-reinforced cement-clay mixture blended with industrial by-product materials has great potential for a wide range of applications in subgrade reinforcement.

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.

scholarly journals Compressive Strength Prediction of Stabilized Dredged Sediments Using Artificial Neural Network

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Van Quan Tran
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Compressive Strength ◽  
Water Content ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Ann Model ◽  
Dredged Sediments ◽  
Important Input ◽  
Artificial Neural

Stabilized dredged sediments are used as a backfilling material to reduce construction costs and a solution to environmental protection. Therefore, the compressive strength is an important criterion to determine the stabilized dredged sediments application such as road construction, building construction, and highway construction. Using the traditional method such as empirical approach and experimental methods, the determination of compressive strength of stabilized dredged sediments is difficult due to the complexity of this composite material. In this investigation, the artificial neural network (ANN) model is introduced to forecast the compressive strength. To perform the simulation, 51 experimental datasets were collected from the literature. The dataset consists of 4 input variables (water content, cement content, air foam content, and waste fishing net content) and output variable (compressive strength). Evaluation of the models was made and compared on training dataset (70% data) and testing dataset (30% remaining data) by the criteria of Pearson’s correlation coefficient (R), Mean Absolute Error (MAE), and Root Mean Square Error (RMSE). The results show that the ANN model can accurately predict the compressive strength of stabilized dredged sediments with low water content. The cement content is the most important input affecting the unconfined compressive strength. The important input affecting the unconfined compressive strength can be in the following order: cement content > air foam content > water content > waste fishing net.

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