Investigation on cement-improved phyllite based on the vertical vibration 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.

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Influencing Factors and Prediction Model for the Antierosion Performance of Cement-Improved Loess Compacted Using Different Compaction Methods

Advances in Materials Science and Engineering ◽

10.1155/2021/1788526 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Kejia Yuan ◽

Yingjun Jiang ◽

Luyao Cai ◽

Jiangtao Fan ◽

Changqing Deng ◽

...

Keyword(s):

Compressive Strength ◽

Prediction Model ◽

Mass Loss ◽

Influencing Factors ◽

Cement Content ◽

Vertical Vibration ◽

Design Criteria ◽

Strength Deterioration ◽

Vibration Compaction ◽

Compaction Method

To analyze the antierosion performance of cement-improved loess (CIL), several influencing factors have been investigated based on two different compaction methods, which include the quasi-static compaction method (QSCM) and the vertical vibration compaction method (VVCM). Then, a prediction model for the cumulative erosion mass loss (CEML) has been established. The effects of erosion on the strength deterioration of CIL were also studied. The results show that, compared with QSCM, specimens compacted using the VVCM have better antierosion performance. As the cement content and the compaction coefficient are increased by 1%, the antierosion performance is increased by 16% and 6.2%, respectively. The eroding time has a significant effect on the antierosion performance of CIL, and the CEML increases linearly with an increase in the eroding time. The compressive strength of CIL decreases significantly due to erosion, and based on the average deterioration degree of the specimens, the design criteria for strength of CIL are proposed, which can provide reference for the design of CIL.

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Laboratory Experimental Research on Mix Ratio Test of Cement Soil

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.438-439.197 ◽

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.

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Cement-Modified Loess Base for Intercity Railways: Mechanical Strength and Influencing Factors Based on the Vertical Vibration Compaction Method

Materials ◽

10.3390/ma13163643 ◽

2020 ◽

Vol 13 (16) ◽

pp. 3643

Author(s):

Yingjun Jiang ◽

Qilong Li ◽

Yong Yi ◽

Kejia Yuan ◽

Changqing Deng ◽

...

Keyword(s):

Mechanical Strength ◽

High Speed ◽

Cement Content ◽

Vertical Vibration ◽

Initial Growth ◽

High Speed Railway ◽

Growth Properties ◽

Vibration Compaction ◽

Growth Equations ◽

Compaction Method

Cement-modified loess has been used in the recent construction of an intercity high-speed railway in Xi’an, China. This paper studies the mechanical strength of cement-modified loess (CML) compacted by the vertical vibration compaction method (VVCM). First, the reliability of VVCM in compacting CML is evaluated, and then the effects of cement content, compaction coefficient, and curing time on the mechanical strength of CML are analyzed, establishing a strength prediction model. The results show that the correlation of mechanical strength between the CML specimens prepared by VVCM in the laboratory and the core specimens collected on site is as high as 83.8%. The mechanical strength of CML initially show linear growth with increasing cement content and compaction coefficient. The initial growth in CML mechanical strength is followed by a later period, with mechanical strength growth slowing after 28 days. The mechanical strength growth properties of the CML can be accurately predicted via established strength growth equations. The results of this study can guide the design and construction of CML subgrade.

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

Geosciences ◽

10.3390/geosciences10060241 ◽

2020 ◽

Vol 10 (6) ◽

pp. 241 ◽

Cited By ~ 3

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.

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

Materials ◽

10.3390/ma14227103 ◽

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.

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Comparative Research on Mechanical Properties and Void Distribution of Cement Stabilized Macadam Based on Static Pressure and Vibration Compaction

Applied Sciences ◽

10.3390/app10248830 ◽

2020 ◽

Vol 10 (24) ◽

pp. 8830

Author(s):

Fuyu Wang ◽

Weichen Pang ◽

Yuan Fang ◽

Yingjun Jiang ◽

Leilei Han ◽

...

Keyword(s):

Mechanical Properties ◽

Static Pressure ◽

Rigid Base ◽

Dry Density ◽

Distribution Characteristics ◽

Engineering Project ◽

Research Results ◽

Void Distribution ◽

Vibration Compaction ◽

Compaction Method

Cement stabilized macadam semi-rigid base materials are widely used in road construction in China. However, a traditional static molding method and heavy compaction method cannot guide the design and engineering application of cement stabilized macadam mixture because it often appears that the compaction degree exceeds 100% in the practical engineering. In view of this, this paper carried out the research of an indoor vibration compaction method of cement stabilized macadam mixture, and compared the mechanical properties and void distribution characteristics of two kinds of compositions of mixtures under the vibration compaction method as well as static pressure molding and heavy compaction method and on-site sample after 7 days curing period, which was combined with the physical engineering project of Yu-Song Expressway in Jilin Province, China. The research results show that the maximum dry density of mixture under vibration compaction is larger and the best moisture content is smaller, which has a heavy incomparable advantage on the simulation of on-site compaction. And the compressive strength and splitting strength indexes of vibration compacted specimens are close to those of an on-site sample, which are all larger than static pressure specimen. Moreover, the void distribution characteristics of vibration compacted specimens is much closer to those of the on-site sample and more universal, while static pressure specimens lack in uniformity. In addition, different results caused by the two gradation are compared. All of the above research results can verify that the vibration compaction method has more reliability and accuracy to simulate the actual properties of base material. This study provides a reference for the application of vibration compaction method in road engineering design.

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Laboratory Study of Engineering Properties of Flowable Backfill Material

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.955-959.2809 ◽

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.

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Mechanical Properties of Sandy Soil Improved with Cement and Nanosilica

Open Engineering ◽

10.1515/eng-2015-0011 ◽

2015 ◽

Vol 5 (1) ◽

Cited By ~ 35

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.

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Comparison of Mechanical Properties of Cement-Stabilized Loess Produced Using Different Compaction Methods

Advances in Materials Science and Engineering ◽

10.1155/2020/4835704 ◽

2020 ◽

Vol 2020 ◽

pp. 1-20

Author(s):

Yingjun Jiang ◽

Kejia Yuan ◽

Qilong Li ◽

Changqing Deng ◽

Yong Yi ◽

...

Keyword(s):

Mechanical Properties ◽

Mechanical Strength ◽

Cement Content ◽

Resilient Modulus ◽

Great Influence ◽

Field Measurements ◽

Vertical Vibration ◽

Dry Density ◽

Curing Time ◽

Compaction Method

Mechanical properties are important indexes to evaluate the improvement effect and engineering performance of cement-stabilized loess (CSL). This paper presents a comparison of the mechanical properties of CSL compacted using hammer quasi-static compaction method (QSCM) and vertical vibration compaction method (VVCM). The compaction properties, unconfined compressive strength (UCS), splitting strength (SPS), and resilient modulus (RM) of the laboratory-compacted CSL using VVCM and QSCM are tested and compared. Furthermore, the effects of compaction method, cement content, compaction coefficient, and curing time of the CSL specimens are investigated. In addition, field measurements are carried out to validate the laboratory investigations. The results show that the laboratory-compacted CSL using VVCM has a larger dry density and smaller optimum water content than that using QSCM. And the compaction method has a great influence on the mechanical strength of CSL. The UCS, SPS, and RM of the specimen produced using VVCM are averagely 1.17 times, 1.49 times, and 1.17 times that of CSL produced using QSCM, respectively, and the UCS, SPS, and RM of the specimens produced using these two methods increase linearly as the cement content and compaction coefficient increase, while the mechanical strength growth curve experiences three periods of increasing sharply, increasing slowly, and stabilizing with the curing time increased. Moreover, the results also show that the mechanical properties of laboratory-compacted CSL using VVCM have a better correlation of 83.8% with the field core samples.

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Research on the Mechanical Properties and Micro-Morphology of the Cement Stabilized Gravel with Rubber Particles

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.470.827 ◽

2013 ◽

Vol 470 ◽

pp. 827-831 ◽

Cited By ~ 1

Author(s):

Ruo Chong Yang ◽

Kai Li ◽

Ji Peng Zhu ◽

Teng Kuo Zhu ◽

Hong Lei Zhu ◽

...

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Cement Paste ◽

Static Pressure ◽

Volume Fraction ◽

Hardened Cement ◽

Hardened Cement Paste ◽

Pressure Method ◽

Rubber Particles ◽

Micro Morphology

The primary objective of this paper was to study the mechanical properties of the cement stabilized gravel by different compact method which added rubber particles by using macroscopic and microscopic test. Through test of compression, relationships of mechanical properties of samples were studied. Pore structure and fractal characteristic of mixture was analyzed quantitatively using mercury intrusion porosimetry (MIP), scanning electron microscope (SEM) was applied to analyze the micro-morphology of samples. The tests results showed that the compressive strength of samples which prepared by using vibrating method was greater than that by static pressure method. Compressive strength of samples from vibrating method or static pressure method decreased with the rubber particles volume fraction increase. MIP tests showed that the mean pore diameter and porosity of mixture increased from about 70nm to 250nm and 9% to 24% with the rubber particles content increasing, respectively. SEM tests showed that the interface bonding between sand and hardened cement paste was better than that of between rubber particles and hardened cement paste.

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