scholarly journals Experimental Study on the Pavement Performance of Cement-Improved Silty Fine Sand

2021 ◽  
Vol 276 ◽  
pp. 02018
Author(s):  
Chen Wei ◽  
Huang Zhijun ◽  
Tang Yulong ◽  
Duan Dahong
Keyword(s):  
Compressive Strength ◽  
Delay Time ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Retention Rate ◽  
Fine Sand ◽  
Ex Post ◽  
Field Compaction ◽  
Desert Areas ◽  
Sand Filler

In view of the fact that there is in shortage of superior roadbed fillers in gobi and desert areas and based on the economical and environment-friendly concept, the cement-improved silty fine sand will be used as the roadbed filler of a railway construction project, which has the engineering characteristics of difficult compaction of local silty fine sands and loose structure, within the territory of Jiuquan, Gansu Province.The test indicated that the actual silty fine sands presented relatively concentrated particle sizes in this project, the particle composition was uniform and difficult to compact. The 7d saturated unconfined compressive strength of the cement-improved silty fine sand filler was correlated with the cement content, curing age and compaction coefficient, and also showed a good linear fitting relation with the cement content. As the delay time of sample molding was lengthened, the 7d saturated unconfined compressive strength of the samples was gradually reduced, and the strength retention rate had a favorable fitting relation with the delay time of sample molding. The compaction coefficient was detected using the sand-cone method in the field compaction test, and on this basis, the “ex post detection” method was proposed to detect the compaction coefficient of this special type of fillers.

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.

Correlation between Unconfined Compressive Strength and Penetration Index Obtained from DCP Tests for Cemented Lateritic Soils

2019 ◽  
Vol 814 ◽  
pp. 399-403
Author(s):  
Anuchit Uchaipichat
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Lateritic Soil ◽  
Test Results ◽  
Cone Penetration ◽  
Penetration Index ◽  
Curing Period ◽  
Cemented Soils ◽  
The Relationship

This paper presents the relationship between the dynamic cone penetration (DCP) test results and the unconfined compressive strength of lateritic cemented soils. A series of DCP tests and unconfined compressive strength was performed on lateritic cemented soil. The soils sample used in this study was lateritic soil. The test results for the DCP tests are presented in terms of penetration index. It can be observed that the penetration index decreased with increasing curing period and cement content. Moreover, the unconfined compressive strength of cemented soils increased with curing period and cement content. The relationship between unconfined compressive strength and penetration index is presented. A unique relationship for unconfined compressive strength can be obtained.

Unconfined Compressive Strength and Drying Shrinkage of Cement Treated Recycling Base at Boyolali-Kartosuro Road Rehabilitation

2012 ◽  
Vol 626 ◽  
pp. 34-38
Author(s):  
Ary Setyawan ◽  
Anastasia Muda ◽  
Sholihin As’ad
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Drying Shrinkage ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
The Road ◽  
Road Base ◽  
Base Materials ◽  
Compressive Strength Test

Road rehabilitation and reconstruction generate large supplies of reclaimed asphalt pavement (RAP). One of the efforts to reuse the RAP is by insitu process and utilize it as road base materials. To get satisfying result from the RAP, it is necessary to add a certain amount of Ordinary Portland Cement (OPC) as stabilizer. This study investigate the potential use of OPC-stabilized RAP in road bases. Laboratory experimental method was applied by using material collected from road located at Boyolali-Kartasura as the object of the study with the cement content variations of 4%, 5% and 6% for unconfined compressive strength test (UCS) and the cement contents variation of 5% and 6% for drying shrinkage test. The range of cement contents required for unconfined compressive strength of cement treated recycling base (CTRB) are 5% to 6%. The cement content used at Boyolali - Kartosuro road rehabilitation was 5.5%. Drying shrinkage during 28 days is 805.3 micro strain for the cement content of 5% and 826.3 micro strain for the cement content of 6%. The drying shrinkage of the materials was quite high for CTRB, so that carefully design and attention need to take into account to avoid the cracks at the road base and the prospective of reflective cracking at the surface course of the road.

Influence of Curing Pressure on Unconfined Compressive Strength of Cemented Clay

2018 ◽  
Vol 928 ◽  
pp. 263-268 ◽  
Author(s):  
Anuchit Uchaipichat
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Soft Clay ◽  
Peak Stress ◽  
Confining Pressure ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Soil Cement ◽  
Curing Pressure

The soil-cement columns are generally installed and cured in the soft clay layers under confining pressure. The strength of the soil-cement columns may be influenced by confining pressure during curing period. In this study, the main objective was to study the influence of curing pressure on unconfined compressive strength of cemented clay. A series of unconfined compression tests was performed on a cement admixed clay sample cured under pressure values of 0 kPa (atmospheric pressure), 25kPa, 50kPa and 100 kPa using a typical unconfined compression equipment. The test samples with values of cement content of 0.5, 1.0 and 2.0 percent were cured for 28 days.The stress-strain curves obtained from all tests show a peak value of stress. The unconfined compressive strength or peak stress obviously increased with increasing cement content for all curing pressure conditions. It can be observed that the strength of samples gradually increased with curing pressure for cement content of 0.5 percent. For cement contents of 1.0 and 2.0 percent, the strengths of samples cured under pressures of 25 kPa dramatically increased from the strength of samples cured without pressure (0 kPa), however, the strengths of samples for curing pressures of 25, 50 and 100 kPa were not clearly different.

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.

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.

scholarly journals The Time Effect and Micromechanism of the Unconfined Compressive Strength of Cement Modified Slurries

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Ping Jiang ◽  
Yewen Chen ◽  
Lin Zhou ◽  
Tianhao Mao ◽  
Wei Wang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Raw Materials ◽  
Time Effect ◽  
Test Results ◽  
X Ray ◽  
Strength Change ◽  
Effect Model ◽  
Curing Age

This study investigated the unconfined compressive strength change law of cement modified slurries (CMS) under different curing ages. We conducted unconfined compressive strength tests using slurry and cement as raw materials. The cement contents were 5%, 10%, 15%, 20%, and 25%. The curing ages were 7, 14, 28, 56, 90, 120, 150, and 180 d. A time effect model of CMS strength was established based on the measured UCS strength-curing age and the strength-cement content curves. The test results proved that the UCS of the CMS increased significantly with an increase in the curing age, and after 90 days, the UCS gradually increased to a fixed value. The time effect model better characterized the relationship between the UCS of the CMS and the curing age and the cement content, as the predicted value had a high correlation with the measured value. We conducted scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) tests to analyze the microstructure and chemical composition of the CMS. The microscopic test results demonstrated that the increase of cement content and curing age increased the amount of gelling substances in the CMS and made the overall structure more compact, thereby increasing its macro strength.

scholarly journals The Effect of Clay Pozzolana-Cement-Composite on the Strength Development of a Hydraulic Backfill

2018 ◽  
Vol 18 (1) ◽  
pp. 32-38
Author(s):  
S. N. Eshun ◽  
Solomon Senyo Robert Gidigasu ◽  
S. K. Y. Gawu
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Unconfined Compressive Strength ◽  
Ordinary Portland Cement ◽  
Cement Content ◽  
Cylindrical Specimen ◽  
Cement Composite ◽  
Strength Development ◽  
Increased Risk ◽  
Economic Considerations

The study sought to investigate the potential application of clay pozzolana as a supplement for cement in hydraulic backfill, using classified tailings from AngloGold Ashanti, Obuasi Mine. The percentage of the Portland cement that could be substituted with the clay pozzolana to produce backfill with best strength was determined. 10%, 25%, 30%, 35% and 40% of the ordinary Portland cement were replaced with clay pozzolana and then mixed with tailings and water. The slurry produced was cast into cylindrical specimen of 50mm diameter by 120mm high and tested for compressive strength after curing for 7, 14, 21, 28 and 56 days. The results indicate that, clay pozzolana-cement composite has potential for application in hydraulic back fill production without increased risk to safety and dilution. It was noted that hydraulic backfill with 10%, 25%, 30% and 35% of the ordinary portland cement replaced with clay pozzolana had strengths greater than those obtained for ordinary portland cement alone. Ten percent (10%) pozzolana content gave the maximum strength followed by 25% pozzolana. It is recommended that for safety and economic considerations, the cement content should be replaced by 25% pozzolana in the production of backfills. Keywords: Hydraulic Backfill, Portland Cement, Clay Pozzolana, Unconfined Compressive Strength

Experimental Investigation on Unconfined Compressive Strength of Cemented Soils Admixed with Saturated GAC

2021 ◽  
Vol 1042 ◽  
pp. 145-150
Author(s):  
Anuchit Uchaipichat
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Unit Weight ◽  
Compression Tests ◽  
Compacted Soil ◽  
Curing Period ◽  
Soil Cement ◽  
Proctor Test ◽  
Cemented Soils

This research investigated the compressive strength of cemented soils admixed with saturated granular activated carbon (GAC). The saturated GAC was obtained from the water filtration system. A series of unconfined compressive strength was performed on both compacted soil-cement specimens and compacted soil-GAC-cement specimens with GAC content of 30 percent. All specimens were prepared by compaction with energy equivalent to the modified Proctor test. The results from modified Proctor tests showed that the maximum dry unit weight and the optimum moisture content of soil-GAC sample was less than those of soil sample. From the unconfined compression tests, there was tiny development of strength for both types of specimens with cement content of 1 percent throughout the curing period of 28 days. For both types of specimens with cement content of 2 and 3 percent, the significant development of strength occurred after curing for 3 days. The strength of specimens typically increased with increasing cement content. Generally, the strength of compacted soil-GAC-cement specimens was less than that of compacted soil- cement specimens. It was also observed that the relationships between normalized compressive strength ratio and curing period was unique for the specimens with the same cement content.

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