Development of a Novel Multifunctional Cementitious-Based Geocomposite by the Contribution of CNT and GNP

In this study, a self-sensing cementitious stabilized sand (CSS) was developed by the incorporation of hybrid carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) based on the piezoresistivity principle. For this purpose, different concentrations of CNTs and GNPs (1:1) were dispersed into the CSS, and specimens were fabricated using the standard compaction method with optimum moisture. The mechanical and microstructural, durability, and piezoresistivity performances, of CSS were investigated by various tests after 28 days of hydration. The results showed that the incorporation of 0.1%, 0.17%, and 0.24% CNT/GNP into the stabilized sand with 10% cement caused an increase in UCS of about 65%, 31%, and 14%, respectively, compared to plain CSS. An excessive increase in the CNM concentration beyond 0.24% to 0.34% reduced the UCS by around 13%. The addition of 0.1% CNMs as the optimum concentration increased the maximum dry density of the CSS as well as leading to optimum moisture reduction. Reinforcing CSS with the optimum concentration of CNT/GNP improved the hydration rate and durability of the specimens against severe climatic cycles, including freeze–thaw and wetting–drying. The addition of 0.1%, 0.17%, 0.24%, and 0.34% CNMs into the CSS resulted in gauge factors of about 123, 139, 151, and 173, respectively. However, the Raman and X-ray analysis showed the negative impacts of harsh climatic cycles on the electrical properties of the CNT/GNP and sensitivity of nano intruded CSS.

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An Investigation into Performance of Cement-Stabilized Kaolinite Clay with Recycled Seashells Exposed to Sulphate

Sustainability ◽

10.3390/su12208367 ◽

2020 ◽

Vol 12 (20) ◽

pp. 8367

Author(s):

Amin Chegenizadeh ◽

Mahdi Keramatikerman ◽

Faizan Afzal ◽

Hamid Nikraz ◽

Chee Keong Lau

Keyword(s):

Magnesium Sulphate ◽

Dry Density ◽

X Ray Diffraction ◽

Maximum Dry Density ◽

Kaolinite Clay ◽

X Ray ◽

Sulphate Concentration ◽

Stabilized Soil ◽

Key Issues ◽

Negative Impacts

Sulphate attack is one of the key issues in geotechnical engineering. This study aims to investigate the efficacy of the seashell to reduce negative impacts of the magnesium sulphate concentration on the cement-stabilized clay mixtures by performing a series of unconfined compressive strength (UCS) tests. Three percent of cement (3, 5 and 7%) was utilized in this study. In addition, the benchmark and exposed specimens were cured for 7, 14, and 28 days before testing and exposure, respectively. A series of the compaction tests were conducted and the optimum moisture content (OMC) and maximum dry density (MDD) values were achieved. In the next stage, the UCS tests were performed on the specimens containing 10, 20, or 30% seashell contents and the specimens were exposed to sulphate concentration. Scanning electron microscope morphology had indicated that seashells are a suitable replacement for cement. Qualitative X-ray diffraction had shown that the presence of magnesium sulphate reduces the formation of calcium silicate hydrate, which causes durability issues in cement-stabilized soils. The results indicated that seashell is effective to improve the sulphate resistance of cement-stabilized soil.

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Toward a better understanding of the effects of cement treatment on microstructural and hydraulic properties of compacted soils

MATEC Web of Conferences ◽

10.1051/matecconf/201816306007 ◽

2018 ◽

Vol 163 ◽

pp. 06007

Author(s):

Harifidy Ranaivomanana ◽

Andry Razakamanantsoa

Keyword(s):

Hydraulic Properties ◽

Silty Sand ◽

Dry Density ◽

Granular Soils ◽

Maximum Dry Density ◽

Compacted Soils ◽

Compaction Method ◽

Different Levels ◽

Standard Compaction

This study deals with the problem of the experimental characterization of cement-treated compacted soils in terms of microstructural and hydraulic properties. Some tests are conducted on two different types of soil: silty sand and clay as fine soils and gravelous sand and alterite as granular soil. Some samples are mixed with 5% of cement and compacted at different levels (i.e., 85%, 95%, 100% and 105% of the maximum dry density, respectively, as achieved using the standard compaction method). The results of the mercury intrusion porosimetry (MIP) tests performed on these cement-treated soils reveal significant changes as regards macropores due to the combined effects of treatment and compaction. Consequently, a decrease in the permeability is clearly observed for all the tested soils when the degree of compaction increases. This decrease is significantly greater in fine soils, which are more sensitive to compaction effects than granular soils.

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Influence of Recycled Concrete Powder (RCP) and Recycled Brick Powder (RBP) on the Physical/Mechanical Properties and Durability of Raw Soil

Coatings ◽

10.3390/coatings11121475 ◽

2021 ◽

Vol 11 (12) ◽

pp. 1475

Author(s):

Li’an Zhou ◽

Yang Liu ◽

Jiacheng Lu ◽

Wenjuan Zhou ◽

Hui Wang

Keyword(s):

Compressive Strength ◽

Water Content ◽

Recycled Concrete ◽

Dry Density ◽

X Ray Diffraction ◽

X Ray ◽

Freeze Thaw ◽

Performance Change ◽

Brick Powder ◽

Research Findings

The influence of recycled concrete powder (RCP) and recycled brick powder (RBP) on the dry density, optimal water content, and compressive strength of raw soil materials was investigated in this study. Moreover, the following resistance of freeze–thaw cycles was also considered. Additionally, X-ray diffraction (XRD) and scanning electron microscope (SEM) were selected to detect its mineral composition and observe the microstructure, further revealing the mechanism of performance change. The mass ratios of recycled concrete powder and recycled brick powder were 2% ~ 14%. Results showed that the dry density decreased and the optimal water content increased with the increasing dosage of recycled concrete powder and recycled brick powder. When the dosage of RCP or RBP was lower than 14%, raw soil with RCP showed higher optimal water content and lower dry density. However, when the dosage was higher than 14%, the result was the opposite. The addition of recycled concrete powder and recycled brick powder was able to decrease the compressive strength of raw soil, except for 10% of recycled brick powder. Raw soil with recycled brick powder presented higher compressive strength than that of raw soil with recycled concrete powder. RBP could improve the freeze–thaw cycles’ resistance of specimens; however, RCP led to decreasing the resistance of freeze–thaw cycles. These research findings can provide reference to the recycling of construction waste.

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A novel device for inclined compaction test on soils

MATEC Web of Conferences ◽

10.1051/matecconf/201819202054 ◽

2018 ◽

Vol 192 ◽

pp. 02054

Author(s):

Panu Promputthangkoon ◽

Tavorn Kuasakul

Keyword(s):

Soil Sample ◽

Soil Compaction ◽

Lateritic Soil ◽

Dry Density ◽

Maximum Dry Density ◽

Sloping Ground ◽

Novel Device ◽

Compaction Test ◽

The Right ◽

Standard Compaction

It can be said that the soil compaction test is currently the standard method for obtaining the right amount of water to be added in order to achieve a maximum dry density. Then, the water content obtained from laboratory work, known as optimum moisture content, is utilised in the field for compacting the soil. It should be noted that the compaction test is carried out on a soil sample prepared in a mould horizontally laid. In the field, however, quite often the compaction is done on side embankments or sloping grounds. Hence, using the laboratory result to control the field density for such cases is problematic. Therefore, this study developed a device that could be used to conduct the compaction test concerning the following conditions: (1) compaction is vertically applied to a soil sample inclined at various angles (VC), and (2) compaction is normal to an inclined soil sample (IC). Some initial tests on lateritic soil using both methods developed showed that at the same energy applied the densities are quite different. These results confirm that, in the case of sloping ground, the standard compaction test may not be appropriate.

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Durability Aspects of Chemically Stabilized Quarry By-Product Applications in Pavement Base and Subbase

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198120919113 ◽

2020 ◽

Vol 2674 (6) ◽

pp. 339-350

Author(s):

Issam I. A. Qamhia ◽

Erol Tutumluer ◽

Hasan Ozer ◽

Huseyin Boler ◽

Heather Shoup ◽

...

Keyword(s):

Recycled Aggregates ◽

Dry Density ◽

Oxide Content ◽

Freezing And Thawing ◽

Maximum Dry Density ◽

Freeze Thaw ◽

High Calcium ◽

Field Samples ◽

Pavement Testing ◽

Drying Conditions

Recent research conducted at the Illinois Center for Transportation evaluated sustainable applications of quarry by-products (QB) or QB blended with coarse recycled aggregates in chemically stabilized base and subbase layers in flexible pavements and proved that stabilized QB pavement applications show satisfactory pavement performance. This paper investigates the durability aspects of the evaluated QB applications, particularly in relation to freezing–thawing cycles during winter and wetting–drying conditions. Durability tests were conducted on samples extracted from field test sections previously evaluated with accelerated pavement testing (APT) as well as on new samples prepared in the laboratory with the same QB types and material combinations. Field-extracted samples were exposed to multiple cycles of freezing and thawing and wetting and drying throughout APT. Both sets of samples were evaluated by AASHTO T 135 and AASHTO T 136 for wet–dry and freeze–thaw durability, respectively. The results of durability testing indicated that cement-stabilized QB materials benefited from the long-term curing in the field, whereas fly ash-stabilized QB materials were less durable after exposure to multiple freeze–thaw and wet–dry cycles in the field. Field samples compacted at or near the maximum dry density (i.e., having higher relative densities) consistently showed better performance for durability. Further, durability samples made with QB materials from dolomitic aggregate sources, having higher magnesium oxide content in chemical composition, showed better field performances than those with limestone QB having high calcium oxide content. This was possibly linked to cementation observed in the dolomitic QB applications after being exposed to freeze–thaw cycles in three winters.

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Influence of Laboratory Compaction Method on Compaction and Strength Characteristics of Unbound and Cement-Bound Mixtures

Applied Sciences ◽

10.3390/app11114750 ◽

2021 ◽

Vol 11 (11) ◽

pp. 4750

Author(s):

Matija Zvonarić ◽

Ivana Barišić ◽

Mario Galić ◽

Krunoslav Minažek

Keyword(s):

Cement Content ◽

Road Construction ◽

Test Methods ◽

Strength Characteristics ◽

Dry Density ◽

Maximum Dry Density ◽

Optimal Moisture Content ◽

Proctor Test ◽

Base Course ◽

Compaction Method

During road construction, granular materials for the unbound base course (UBC) and cement-bound base course (CBC) are mostly compacted by vibratory rollers. A widespread laboratory test for determining the optimal moisture content (OMC) and maximum dry density (MDD) of the mixture for installation in UBC and CBC is the Proctor test. Considering that the Proctor test does not produce any vibrations during compaction, this paper compares the Proctor test and the vibrating hammer test. The examination was conducted on UBC and CBC with varying cement content and aggregate types. All mixtures were compacted by both methods with the aim of determining the compaction and strength characteristics. The results indicated the high comparability of the two test methods for mixtures with natural aggregate in terms of MDD, OMC, density and strength characteristics (California bearing ratio (CBR) for UBC and 28-day compressive strength for CBC). For mixtures with higher cement content, the OMC difference depending on the laboratory compaction method used can be significant, so the laboratory compaction method should be chosen carefully, particularly for moisture-susceptible materials. This paper also reveals that by increasing the proportion of rubber in the mixture, the compaction and strength characteristics differ significantly due to the compaction method. Therefore, when using alternative and insufficiently researched materials, the compaction method should also be chosen carefully.

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CLAYEY SOIL TREATED BY CEMENT AND QUICKLIME BY MICROSTRUCTURE: A MINERALOGICAL ANALYSIS

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2019.43 ◽

2019 ◽

Vol 6 (1) ◽

Author(s):

Husam Hikmat Baqir ◽

Aqeel Al-Adili ◽

Kawther Al-Soudany ◽

Ali Shareef

Keyword(s):

Clay Soil ◽

Clayey Soil ◽

Dry Weight ◽

Dry Density ◽

Hydration Reaction ◽

X Ray Diffraction ◽

Mineralogical Analysis ◽

Maximum Dry Density ◽

X Ray ◽

Scanning Electron

Soft clayey soil was treated by a combination of cement (PC) and Quicklime (LQ) in order to modify and stability. This study shows an improvement of clay soil brought from Garma Ali site in the Al Basra governorate, Iraq. The PC was added in percentages of 0, 2, 4, 6, 8, and 10%, and LQ was added to 2 and 4%, of dry weight. Also, this research used Microstructure Analysis by Scanning Electron Microscope (SEM) testing and Mineralogical Analysis by X-Ray Diffraction (XRD) testing on the examination soil treated with mix between cement (PC) and Quicklime (LQ) for the purpose of knowing the reasons for the increase in the shear strength and decrease maximum dry density. Through the micrographs that result from the scanning electron microscoping and the curves of X-ray that demonstrate presentence, the formation of the hydration reaction product (CSH gel) shows tiny bristle (rod) crystals. The CSH gel and the tiny bristle (rod) crystals worked on coating and contact the particles together. The micrographs for soils treated with (2% LQ + 10% PC) show an increase in the amount hydrated gel (CSH) compared to the soil treated with 6% PC and 2% LQ and 8% PC and 4% LQ, but the number of bristle-like crystals decreases compared to soil treated by 8% PC and 4% LQ.

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An analysis of the factors influencing the relationship between soil properties and optimum moisture content and the formulation of an abbreviated test method of determinig maximum dry density

10.51415/10321/2892 ◽

1997 ◽

Author(s):

◽

Anthony James Allinsin

Keyword(s):

Moisture Content ◽

Liquid Limit ◽

Optimum Moisture Content ◽

Test Method ◽

Dry Density ◽

Maximum Dry Density ◽

Strength And Durability ◽

The Relationship ◽

Standard Compaction

The strength and durability of any soil structure is dependent on the quality of the compaction of the soil. This quality is measured by employing a standard compaction test, which provides a standard with which density may be compared, called the maximum dry density, and the moisture content of the soil at which this is achieved, called the optimum moisture content. As a matter of routine during quality control, the particle size distribution, plasticity index and liquid limit of the soil are determined at the same time as its maximum dry density and optimum moisture content.

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The Preliminary Study on The Effect of Coarse Particles Content on OMC and Maximum Dry Unit Weight: A Case of Aceh’s Fill Materials

Aceh International Journal of Science and Technology ◽

10.13170/aijst.5.2.4877 ◽

2016 ◽

Vol 5 (2) ◽

Cited By ~ 1

Author(s):

Bambang Setiawan

Keyword(s):

Coarse Fraction ◽

Coarse Grained ◽

Unit Weight ◽

Dry Density ◽

Coarse Particles ◽

Maximum Dry Density ◽

Engineering Construction ◽

The Relationship ◽

Standard Compaction ◽

Fill Materials

Empirical evidence suggests that the percentage of coarse fraction content on soil has an influence on the soil optimum moisture content (OMC) and soil maximum dry density (MDD). This phenomenon is used as a basis to examine the characteristics of Aceh’s fill materials. The major objective of the present study is to determine the relationship between coarse-grained content and OMC and MDD of the Aceh’s fill materials. This relationship is important in the justification of soil suitability as materials for engineering construction. Thirty (30) soil samples from various locations in the Province of Aceh have been collected and tested. The tests carried out include soil physical properties tests and standard compaction test. In the case of a relationship between soil coarse fraction content and soil OMC or MDD, two general findings have been deduced. The first finding of the present study shows that the soil OMC decreases when the content of coarse-grained particles in the soil increases. The later finding shows a positive correlation between coarse particles content and the soil MDD which the increase of the content of coarse-grained particles in the soil will increase the value of the soil’s MDD. In conclusion, the coarse particles content affects the OMC and MDD of Aceh’s fill materials

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The performance of ultra-lightweight foamed concrete incorporating nanosilica

Archives of Civil and Mechanical Engineering ◽

10.1007/s43452-021-00234-2 ◽

2021 ◽

Vol 21 (2) ◽

Author(s):

Mohamed Abd Elrahman ◽

Pawel Sikora ◽

Sang-Yeop Chung ◽

Dietmar Stephan

Keyword(s):

Wall Thickness ◽

Probabilistic Approach ◽

Drying Shrinkage ◽

Dry Density ◽

Optimal Dosage ◽

X Ray ◽

Mechanical And Physical Properties ◽

Fresh State ◽

Foamed Concrete ◽

The Stability

AbstractThis paper aims to investigate the feasibility of the incorporation of nanosilica (NS) in ultra-lightweight foamed concrete (ULFC), with an oven-dry density of 350 kg/m3, in regard to its fresh and hardened characteristics. The performance of various dosages of NS, up to 10 wt.-%, were examined. In addition, fly ash and silica fume were used as cement replacing materials, to compare their influence on the properties of foamed concrete. Mechanical and physical properties, drying shrinkage and the sorption of concrete were measured. Scanning electron microscopy (SEM) and X-ray microcomputed tomography (µ-CT) and a probabilistic approach were implemented to evaluate the microstructural changes associated with the incorporation of different additives, such as wall thickness and pore anisotropy of produced ULFCs. The experimental results confirmed that the use of NS in optimal dosage is an effective way to improve the stability of foam bubbles in the fresh state. Incorporation of NS decrease the pore anisotropy and allows to produce a foamed concrete with increased wall thickness. As a result more robust and homogenous microstructure is produced which translate to improved mechanical and transport related properties. It was found that replacement of cement with 5 wt.-% and 10 wt.-% NS increase the compressive strength of ULFC by 20% and 25%, respectively, when compared to control concrete. The drying shrinkage of the NS-incorporated mixes was higher than in the control mix at early ages, while decreasing at 28 d. In overall, it was found that NS is more effective than other conventional fine materials in improving the stability of fresh mixture as well as enhancing the strength of foamed concrete and reducing its porosity and sorption.

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