Using of Untreated Carbon Nanotubes in Cement Compositions

2016 ◽  
Vol 865 ◽  
pp. 6-11 ◽  
Author(s):  
Kateryna Pushkarova ◽  
Maryna Sukhanevych ◽  
Artur Martsikh
Keyword(s):  
Carbon Nanotubes ◽  
Cement Paste ◽  
Cementitious Materials ◽  
Positive Influence ◽  
Mechanical Tests ◽  
Strength Characteristics ◽  
Concrete Durability ◽  
Cement Mortars ◽  
Optimum Decision ◽  
Cement System

One of the most important problem of concrete durability is increasing of waterproofing. Researches are devoted studying of cement mortars modified by carbon nanotubes, dispersed in plasticizers solutions. Were investigated physico-mechanical properties of cement paste, cement-sand mortar into which structure entered untreated carbon nanotubes (production of plant TM "Spetsmash" Kyiv, Ukraine) in various quantity. Were used as plasticizers in cement compositions additives substances of the various chemical nature – naphtaleneformaldehyde, melamineformaldehyde and polycarboxylate. Quantity of untreated nanotubes varied from 0,5%; 1,0% and to 1,5%. Concentration of additives was accepted taking into account recommendations of producers and made about 1% from the weight of cement. Were studied some technological processes of introduction untreated carbon nanotubes in cement system and is shown that the way of introduction of nanomodifiers has essential impact on strength characteristics of cementitious materials. Optimum decision introduction of untreated carbon nanotubes is using its in dispersion plasticizer of the working concentration prepared in an ultrasonic dispergator is established. Results of physico-mechanical tests of cement paste and cement-sand mortar showed positive influence at introduction of untreated carbon nanotubes as cement modifiers on strength characteristics of samples. Resalts is shown that the nanomodifier, used quantity about 1% in solution of lignosulfonate with polycarboxylate and melamineformaldehyde plasticizer has great impact on strength characteristics.

The Combined Effect of the Plasticizer and Multi-Walled Carbon Nanotubes on the Cement Hydration Products

2018 ◽  
Vol 276 ◽  
pp. 21-26
Author(s):  
Gintautas Skripkiūnas ◽  
Grigory Ivanovich Yakovlev ◽  
Ekaterina Karpova ◽  
Anastasiia Gordina ◽  
Arina Shaybadullina
Keyword(s):  
Carbon Nanotubes ◽  
Cement Paste ◽  
Cement Hydration ◽  
Hardened Cement ◽  
Hydration Products ◽  
Hardened Cement Paste ◽  
Physico Chemical ◽  
Cement System ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

There are many research devoted to the influence of carbon nanotubes (CNT) on the structure and properties of cement systems. In the course of this research, the combined influence of of multi-walled carbon nanotubes (MWCNT) and polycarboxylate (PCE) plasticizer on the products of hydration and the properties of hardened cement paste was investigated. The strength characteristics of nanomodified hardened cement paste and the hydration products were determined by the usage of modern methods of physico-mechanical and physico-chemical analyses. Based on the physico-chemical investigations, it was concluded the necessity of additional experiments, associated primary with questions of uniform distribution of the nanostructures and their chemical interactions with another components of admixture and cement system.

scholarly journals Experimental study of the behaviour of cement pastes in the presence of carbon nanotubes

2019 ◽  
Author(s):  
Ritoltas Šukys ◽  
Jolanta Pranckevičienė ◽  
Giedrius Girskas ◽  
Ina Pundienė ◽  
Dainius Leonavičius ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Dynamic Viscosity ◽  
Methyl Cellulose ◽  
Physical And Mechanical Properties ◽  
Previous Treatment ◽  
Cementitious Materials ◽  
Mechanical Tests ◽  
Cement Pastes ◽  
Multi Walled Carbon Nanotubes ◽  
Compressive And Flexural Strengths

One of the methods recently applied for the noticeably improvement of properties of cementitious materials is the use of the single or multi-walled carbon nanotubes (CNTs) as nano-reinforcements in cementitious materials. The positive action of CNTs highly depends not only on its nature, length and amount, but also on previous treatment of CNTs and quality of CNTs dispersion. It is important to obtain the effects of multi-walled CNTs, dispersed only in carboxyl-methyl cellulose – commercially available pellets without the use of any commercially available surfactants or plasticizers. The influence of dispersed CNTs on the rheological properties of fresh cement pastes and physical and mechanical properties of hardened specimens was analyzed in this work. Compared to the dynamic viscosity of pure distilled water smaller amounts of CNTs (0.00005–0.005%) reduce the dynamic viscosity down to the 15% whereas higher amounts of CNTs (0.05–0.5%) increase the dynamic viscosity from 1.3 to 4.7 times. Mechanical tests of hardened for 28 days cement paste specimens showed that smaller amounts of CNTs (0.00005–0.005%) increase the compressive and flexural strengths by 38.07– 42.3% and 40.1– 44.6%, whereas higher amounts of CNTs (0.05–0.5%) increase these strengths just by 21.11–18.82% and 18.33–6.6% respectively.

scholarly journals Effects of carbon nanotubes on expanded glass and silica aerogel based lightweight concrete

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Suman Kumar Adhikary ◽  
Žymantas Rudžionis ◽  
Simona Tučkutė ◽  
Deepankar Kumar Ashish
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Silica Aerogel ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Cementitious Materials ◽  
Lightweight Aggregate Concrete ◽  
Multi Wall Carbon Nanotubes ◽  
Sem Image ◽  
Study Results

AbstractThis study is aimed to investigate the effect of carbon nanotubes on the properties of lightweight aggregate concrete containing expanded glass and silica aerogel. Combinations of expanded glass (55%) and hydrophobic silica aerogel particles (45%) were used as lightweight aggregates. Carbon nanotubes were sonicated in the water with polycarboxylate superplasticizer by ultrasonication energy for 3 min. Study results show that incorporating multi-wall carbon nanotubes significantly influences the compressive strength and microstructural performance of aerogel based lightweight concrete. The addition of carbon nanotubes gained almost 41% improvement in compressive strength. SEM image of lightweight concrete shows a homogeneous dispersal of carbon nanotubes within the concrete structure. SEM image of the composite shows presence of C–S–H gel surrounding the carbon nanotubes, which confirms the cites of nanotubes for the higher growth of C–S–H gel. Besides, agglomeration of carbon nanotubes and the presence of ettringites was observed in the transition zone between the silica aerogel and cementitious materials. Additionally, flowability, water absorption, microscopy, X-ray powder diffraction, and semi-adiabatic calorimetry results were analyzed in this study.

scholarly journals Stabilizing effect of methylcellulose on the dispersion of multi-walled carbon nanotubes in cementitious composites

2020 ◽  
Vol 9 (1) ◽  
pp. 93-104
Author(s):  
Mingrui Du ◽  
Yuan Gao ◽  
Guansheng Han ◽  
Luan Li ◽  
Hongwen Jing
Keyword(s):  
Carbon Nanotubes ◽  
Pore Solution ◽  
Cementitious Materials ◽  
High Ionic Strength ◽  
Cementitious Composites ◽  
Uniform Distributions ◽  
Stabilizing Effect ◽  
Multi Walled Carbon Nanotubes ◽  
The Stability ◽  
Walled Carbon Nanotubes

AbstractMulti-walled carbon nanotubes (MWCNTs) have been added in the plain cementitious materials to manufacture composites with the higher mechanical properties and smart behavior. The uniform distributions of MWCNTs is critical to obtain the desired enhancing effect, which, however, is challenged by the high ionic strength of the cement pore solution. Here, the effects of methylcellulose (MC) on stabilizing the dispersion of MWCNTs in the simulated cement pore solution and the viscosity of MWCNT suspensions werestudied. Further observations on the distributions of MWCNTs in the ternary cementitious composites were conducted. The results showed that MC forms a membranous envelope surrounding MWCNTs, which inhibits the adsorption of cations and maintains the steric repulsion between MWCNTs; thus, the stability of MWCNT dispersion in cement-based composites is improved. MC can also work as a viscosity adjuster that retards the Brownian mobility of MWCNTs, reducing their re-agglomerate within a period. MC with an addition ratio of 0.018 wt.% is suggested to achieve the optimum dispersion stabilizing effect. The findings here provide a way for stabilizing the other dispersed nano-additives in the cementitious composites.

scholarly journals Effect of High-Dispersible Graphene on the Strength and Durability of Cement Mortars

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 915
Author(s):  
Xiaoqiang Qi ◽  
Sulei Zhang ◽  
Tengteng Wang ◽  
Siyao Guo ◽  
Rui Ren
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Cement Mortar ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Chloride Ion Penetration ◽  
Cement Mortars ◽  
Strength And Durability ◽  
Durability Performance

Graphene’s outstanding properties make it a potential material for reinforced cementitious composites. However, its shortcomings, such as easy agglomeration and poor dispersion, severely restrict its application in cementitious materials. In this paper, a highly dispersible graphene (TiO2-RGO) with better dispersibility compared with graphene oxide (GO) is obtained through improvement of the graphene preparation method. In this study, both GO and TiO2-RGO can improve the pore size distribution of cement mortars. According to the results of the mercury intrusion porosity (MIP) test, the porosity of cement mortar mixed with GO and TiO2-RGO was reduced by 26% and 40%, respectively, relative to ordinary cement mortar specimens. However, the TiO2-RGO cement mortars showed better pore size distribution and porosity than GO cement mortars. Comparative tests on the strength and durability of ordinary cement mortars, GO cement mortars, and TiO2-RGO cement mortars were conducted, and it was found that with the same amount of TiO2-RGO and GO, the TiO2-RGO cement mortars have nearly twice the strength of GO cement mortars. In addition, it has far higher durability, such as impermeability and chloride ion penetration resistance, than GO cement mortars. These results indicate that TiO2-RGO prepared by titanium dioxide (TiO2) intercalation can better improve the strength and durability performance of cement mortars compared to GO.

Effect of Water-Soluble Carbon Nanotubes on the Mechanical Properties and early Hydration of Alkali-Activated Slag

2014 ◽  
Vol 1000 ◽  
pp. 118-121 ◽  
Author(s):  
Pavel Rovnaník ◽  
Patrik Bayer
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Cementitious Materials ◽  
Water Soluble ◽  
Strength Parameters ◽  
Early Hydration ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Hydration Characteristics ◽  
Alkali Activated

Alkali-activated slag (AAS) is a material which has great potential for use in building industry. The aim of this work was to gain new superior properties by the addition of carbon nanotubes (CNTs). This material can act as a microreinforcement improving mechanical properties of cementitious materials. The effect of 0–1 wt.% addition of CNTs on the mechanical properties, hydration characteristics and microstructure of AAS binder was determined. The addition of CNTs delays the setting of the binder and a partial deterioration of strength parameters was observed.

Use of Algerian Natural Mineral Deposit as Supplementary Cementitious Materials

2018 ◽  
Vol 34 ◽  
pp. 48-58 ◽  
Author(s):  
Karima Arroudj ◽  
Saida Dorbani ◽  
Mohamed Nadjib Oudjit ◽  
Arezki Tagnit-Hamou
Keyword(s):  
Mechanical Strength ◽  
Calcium Hydroxide ◽  
Cement Paste ◽  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Heat Of Hydration ◽  
Cement Industry ◽  
Supplementary Cementitious Materials ◽  
Natural Mineral ◽  
Different Ages

Much of the current research on concrete engineering has been focused on including siliceous additions as supplementary cementitious materials (SCMs). Silica reacts with Calcium hydroxide release during cement hydration, and produces more C-S-H. The latter contributes to increase compactness, mechanical strengths and sustainability of concrete. This paper explores the hydration characteristics of cement paste based on various natural mineral additions, that are very abundant in Algeria and present a high silica content (ground natural pozzolana “PZ” and ground dune sand “DS”). For this purpose, several analyses were carried out on modified cement pastes and mortars. TheseSCMswere introduced by replacement levels of 15, 20 and 25 by weight of cement. We first, studied the effect of these SCMs on the heat of hydration and mechanical strength of mortars at different ages. The evolution of hydration of modified paste was studied, by using Thermal analysis (TG/TDA) at different ages, to analyze the Calcium Hydroxide (CH) content of the modified pastes. It is shown that the CH content of the mixes including SCMs is lower than that of the plain cement paste, indicating that silica reacts with the cement paste through a pozzolanic reaction. Increased pozzolanic activity results in higher amounts of Calcium Silicate Hydrate in the paste, which in turn results in higher compressive strength for modified cement mortars. Due to its crystalline morphology, the ground DS particles present a partial pozzolanic effect, compared to PZ which is semi-crystalline. Modified mortars by 20% DS can be the optimal composition. It presents satisfactory results: good mechanical strength and low heat of hydration. It can lead to an economic and sustainable concrete. Ground DS is very abounded in Africa and free of any impurities and can be a good alternativeSCMsin cement industry.

Sign in / Sign up

Export Citation Format

Share Document