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

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.

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.814.399 ◽

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.

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Effects of Crumb Rubber on Compressive Strength of Cement-Treated Soil

Archives of Civil Engineering ◽

10.1515/ace-2015-0036 ◽

2015 ◽

Vol 61 (4) ◽

pp. 59-78 ◽

Cited By ~ 13

Author(s):

F. C. Wang ◽

W. Song

Keyword(s):

Compressive Strength ◽

Cement Content ◽

Rubber Particle ◽

Crumb Rubber ◽

Test Results ◽

Rubber Content ◽

Strength Tests ◽

Strength And Stiffness ◽

Cement Soil ◽

Curing Age

A study was undertaken to investigate the effects of crumb rubber on the strength and mechanical behaviour of Rubberized cement soil (RCS). In the present investigation, 26 groups of soil samples were prepared at five different percentages of crumb rubber content, four different percentages of cement content and two different finenesses of crumb rubber particle. Compressive strength tests were carried out at the curing age of 7 days, 14 days, 28 days and 90 days. The test results indicated that the inclusion of crumb rubber within cement soil leads to a decrease in the compressive strength and stiffness and improves the cement soil’s brittle behaviour to a more ductile one. A reduction of up to 31% in the compressive strength happened in the 20% crumb content group. The compressive strength increases with the increase in the cement content. And the enlargement of cement content is more efficient at low cement content.

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Experimental study on unconfined compressive strength of expansive soil improved by lignin and cement

E3S Web of Conferences ◽

10.1051/e3sconf/202123602010 ◽

2021 ◽

Vol 236 ◽

pp. 02010

Author(s):

Yuguo Zhang ◽

Weijie Zhang ◽

Xiaojie Shi ◽

Tai Guo ◽

Zhenghao Chen

Keyword(s):

Compressive Strength ◽

Unconfined Compressive Strength ◽

Lignin Content ◽

Expansive Soil ◽

Test Results ◽

Soil Particles ◽

Compressive Strength Test ◽

Improvement Method ◽

Compaction Degree ◽

Curing Age

Aiming at the question of improvement expansive soil in Nanyang area, the composite improvement method of lignin and cement was adopted. Based on the unconfined compressive strength test, the variation law of unconfined compressive strength of improved expansive soil with different lignin content, different compaction degree and different curing age was studied. The test results show that the composite of lignin and cement can effectively improve the unconfined compressive strength of expansive soil. The unconfined compressive strength of L-C (lignin and cement) improved expansive soil reaches the maximum when the cement content is fixed at 4% and the lignin content is 1%. The unconfined compressive strength of L-C improved soil increases with the increase of compaction degree and curing age, and the strength growth mainly concentrated in the first 7 days of curing age. From the point of improvement mechanism, the hydration and gelation reaction of cement occur in expansive soil, and gel material with higher strength is formed to enhance the strength of expansive soil. The appropriate amount of lignin can fill the pores between soil particles and make the connection between soil particles more closely, so as to improve the strength of expansive soil.

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Analysis of Influencing Factors and Mechanism of Strength of Cement-Modified Silty Sand

Geofluids ◽

10.1155/2021/9414234 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Weidong Jin ◽

Zhe Wang ◽

Yongming Ai ◽

Chenyang Liu

Keyword(s):

Compressive Strength ◽

Power Function ◽

Unconfined Compressive Strength ◽

Cement Content ◽

Soil Strength ◽

Silty Sand ◽

Logarithmic Relationship ◽

Cement Soil ◽

Comprehensive Characterization ◽

Curing Age

The unconfined compressive strength of cement-modified silty sand in Jilin Province was investigated in this study. For this purpose, various tests were conducted, including the screening test, compaction test, CBR test, X-ray fluorescence detection, and unconfined compressive strength test. Effects of compaction degree, soil quality, water quality, cement content, and curing age were considered. The results show that CBR value is positively correlated with compactness. Two kinds of different water qualities have little effect on unconfined compressive strength of cement-improved soil; with the increase in cement content, the unconfined compressive strength increases, and the power function equation established by the two is significantly correlated. The logarithmic relationship between cement-soil strength and curing age is approximately linear. Through regression analysis, the comprehensive characterization parameters of cement-soil strength, such as water-cement ratio, cement content, and curing age, are put forward. The unconfined compressive strength of cement-modified silty sand has a good power function relationship with the comprehensive characterization parameters, and the fitting degree between the strength prediction formula and the existing research and test data exceeds 90%, which verifies the effectiveness of the comprehensive characterization parameters.

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Experimental Study on the Performance of Compound Improved HLLS (High Liquid Limit Soil) with Various Curing Agents

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.753.300 ◽

2017 ◽

Vol 753 ◽

pp. 300-304 ◽

Cited By ~ 1

Author(s):

Yun Que ◽

Yi Qian Lin ◽

Fang Ze Gong

Keyword(s):

Compressive Strength ◽

Unconfined Compressive Strength ◽

Cement Content ◽

Liquid Limit ◽

Curing Agent ◽

Compressive Strength Test ◽

Curing Agents ◽

The One ◽

Better Than ◽

Curing Age

The HLLS (high liquid limit soil) has the characteristics of high moisture content, low bearing capacity and poor water stability. Most of the existing treatment methods focus on the improvement with a single curing agent, and the research on the improvement of HLLS with various curing agents is still insufficient. This paper presents the characteristics of two kinds of compound improved HLLS based on unconfined compressive strength test. The results show that the unconfined compressive strength of CSIS (Cement / SAP Improved Soil) and CLIS (Cement / Renolith Improved Soil) are greatly improved than those of CIS (Cement Improved Soil) when the curing age is 28d, respectively. The maximum increments of unconfined compressive strength are 0.31MPa and 0.22MPa, respectively. When the cement content is less (more) than 3%, the unconfined compressive strength of CSIS decreases (increases) with the increase of SAP content. When the cement content is constant, the unconfined compressive strength of CLIS increases first and then decreases with the increase of the Renolith content. The optimum mix amount of SAP (Renolith) and cement in CSIS (CLIS) are 0.06% (0.2%) and 5% (3%), respectively. The strength and crack resistance of the two kinds of compound improved soil are better than the one with single curing agent. SAP and Renolith exert the properties of self-curing after water absorption and hydrophobicity, respectively.

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Effect of Fly Ash on Compressive Strength, Drying Shrinkage, and Carbonation Depth of Mortar with Ferronickel-Slag Powder

Applied Sciences ◽

10.3390/app11031037 ◽

2021 ◽

Vol 11 (3) ◽

pp. 1037

Author(s):

Se-Jin Choi ◽

Ji-Hwan Kim ◽

Sung-Ho Bae ◽

Tae-Gue Oh

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Construction Industry ◽

Bituminous Coal ◽

Raw Materials ◽

Drying Shrinkage ◽

The Other ◽

Test Results ◽

Slag Powder ◽

Ferronickel Slag

In recent years, efforts to reduce greenhouse gas emissions have continued worldwide. In the construction industry, a large amount of CO2 is generated during the production of Portland cement, and various studies are being conducted to reduce the amount of cement and enable the use of cement substitutes. Ferronickel slag is a by-product generated by melting materials such as nickel ore and bituminous coal, which are used as raw materials to produce ferronickel at high temperatures. In this study, we investigated the fluidity, microhydration heat, compressive strength, drying shrinkage, and carbonation characteristics of a ternary cement mortar including ferronickel-slag powder and fly ash. According to the test results, the microhydration heat of the FA20FN00 sample was slightly higher than that of the FA00FN20 sample. The 28-day compressive strength of the FA20FN00 mix was approximately 39.6 MPa, which was higher than that of the other samples, whereas the compressive strength of the FA05FN15 mix including 15% of ferronickel-slag powder was approximately 11.6% lower than that of the FA20FN00 mix. The drying shrinkage of the FA20FN00 sample without ferronickel-slag powder was the highest after 56 days, whereas the FA00FN20 sample without fly ash showed the lowest shrinkage compared to the other mixes.

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Experimental Study on Improvement of Marine Soft Soil with Alkali Residue

E3S Web of Conferences ◽

10.1051/e3sconf/20185304021 ◽

2018 ◽

Vol 53 ◽

pp. 04021

Author(s):

SHAO Yong ◽

LIU Xiao-li ◽

ZHU Jin-jun

Keyword(s):

Experimental Study ◽

Compressive Strength ◽

Unconfined Compressive Strength ◽

Void Ratio ◽

Soft Soil ◽

Compressive Modulus ◽

Engineering Properties ◽

Test Results ◽

Use Of Resources ◽

One Year

Industrial alkali slag is the discharge waste in the process of alkali production. About one million tons of alkali slag is discharged in China in one year. It is a burden on the environment, whether it is directly stacked or discharged into the sea. If we can realize the use of resources, it is a multi-pronged move, so alkali slag is used to improve solidified marine soft soil in this paper. The test results show that the alkali residue can effectively improve the engineering properties of marine soft soil. Among them, the unconfined compressive strength and compressive modulus are increased by about 10 times, and the void ratio and plasticity index can all reach the level of general clay. It shows that alkali slag has the potential to improve marine soft soil and can be popularized in engineering.

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Influence of Mix Fly and Bottom Ashes from Biomass on Selected Properties of Cement Mortars

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.828.14 ◽

2019 ◽

Vol 828 ◽

pp. 14-17

Author(s):

Malgorzata Ulewicz ◽

Jakub Jura

Keyword(s):

Electron Microscopy ◽

Compressive Strength ◽

Industrial Waste ◽

Cement Mortar ◽

Raw Materials ◽

Bottom Ash ◽

Waste Materials ◽

X Ray ◽

Cement Mortars ◽

Fluorescence Spectrometer

The preliminary results of utilization of fly and bottom ash from combustion of biomass for the produce of cement mortars has been presented. Currently, this waste are deposited in industrial waste landfills. The chemical composition of waste materials was determined using X-ray fluorescence (spectrometer ARL Advant 'XP). ). In the studies sand was replaced by mix of fly and bottom ash from the combustion of biomass in an amount of 10-30% by weight of cement CEM I 42.5 R (Cemex). The obtained cement mortar concrete were subjected to microscopic examination (LEO Electron Microscopy Ltd.) and their compressive strength (PN-EN-196-1), frost resistance (PN-EN 1015-11 and PN-B -04500 ) and absorbability (PN-85/B-04500) were identified. The obtained results showed, the replacement of the cement by mix ashes from combustion of biomass reduce consumption of raw materials and will have a good influence on the environment.

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Investigation on cement-improved phyllite based on the vertical vibration compaction method

PLoS ONE ◽

10.1371/journal.pone.0247599 ◽

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.

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Preparation of Portland Cement with Gold Ore Tailings

Advances in Materials Science and Engineering ◽

10.1155/2019/1324065 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Qiang Wang ◽

Geng Yao ◽

Xiangnan Zhu ◽

Junxiang Wang ◽

Peng Wu ◽

...

Keyword(s):

Compressive Strength ◽

Flexural Strength ◽

Portland Cement ◽

Raw Materials ◽

Setting Time ◽

Hydration Product ◽

Difficult Problem ◽

Initial Setting Time ◽

Gold Ore ◽

Curing Age

The disposal of gold ore tailings (GTs) has been a very difficult problem for a long time. Thus, this study explored a new approach to the management of GTs by preparing Portland cement. Physical properties, reaction mechanisms, and hydration product types of cement prepared with GTs (C-GTs) and ordinary Portland cement (C-SS) were compared. X-ray diffraction (XRD), thermogravimetric (TG), and scanning electron microscope energy-dispersive spectroscopy (SEM-EDS) analysis techniques were used to study the mineralogical phases of the clinker and raw materials, hydration product types, and microtopography. The consistency, setting time, flexural strength and compressive strength values of the cement samples (C-GTs and C-SS), and burnability of the raw materials were also studied. The burnability analysis indicated that GTs provided a higher reactivity. The XRD results showed that the clinker phases of the C-GTs were C3S, C2S, C3A, and C4AF. The XRD, TG, and SEM-EDS results showed that the hydration products were flaky calcium hydroxide, rod-shaped ettringite, and granular C-S-H gels. Its compressive strength and flexural strength were, respectively, 30.4 MPa and 6.1 MPa at the curing age of 3 days and 59.1 MPa and 9.8 MPa at the curing age of 28 days, which were slightly higher than those of the C-SS. Furthermore, the results showed that the consistency, initial setting time, and final setting time for the two kinds of cement were similar, which further suggested that GTs could be used to prepare Portland cement.

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