Piezoresistive Properties of Cement Mortar with Carbon Nanotube

2011 ◽  
Vol 284-286 ◽  
pp. 310-313
Author(s):  
Zhi Gang Liu ◽  
Li Rong Yang ◽  
Jun Cong Wei ◽  
Bao Hui Zhao ◽  
Xiao Xin Feng

The compressive strength and piezoresistive property of cement mortar with low adding level of multi-walled carbon nanotubes (MWCNTs) were investigated. Experimental results showed that the compressive strength of the MWCNTs/cement mortars increased with the adding amount of MWCNTs content for all the curing ages. Silica fume promoted the compressive strength development by well bonding with MWCNTs and filling effect. The electrical resistance changed synchronously with the compressive strength and the amount of the changes varied with the stress and MWCNTs addition levels. Higher MWCNTs doping level improved the piezoresistive sensitivity of the mortar. The mortar with silica fume (5-10% by weight of cement) exhibited better piezoresistive response than that without silica fume at the same MWCNTs doping levels.

Author(s):  
Pawandeep Kaur ◽  
Jaspal Singh ◽  
Manpreet Kaur ◽  
Ritesh Jain

Metakaolin based geopolymer mortars are presently considered as a feasible substitute to Ordinary Portland Cement mortar due to its various benefits. The present experimental investigation is planned by varying the concentrations of sodium hydroxide as 8M, 10M and 12M along with the variation of multi-walled carbon nanotubes (0, 0.25%, 0.50%, 0.75% and 1% by weight of the binder). For each specimen, the compressive strength was determined at the curing ages of 3, 7 and 28 days. The results clearly indicate that the incorporation of multi walled carbon nanotubes (MWCNTs) in the geopolymer matrixes enhances the compressive strength. Transmission electron microscope (TEM) was used to depict the microstructure and morphology of MWCNTs. The ultimate compressive strength was obtained by employing 12M concentrated sodium hydroxide solution along with 0.5% of MWCNTs in geopolymer mortar. The values of integral absolute error were computed for all the curing ages. All the values lie within the acceptable range (0 to 10%).


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6654
Author(s):  
Jakub Popławski ◽  
Małgorzata Lelusz

Biomass combustion is a significant new source of green energy in the European Union. The adequate utilization of byproducts created during that process is a growing challenge for the energy industry. Biomass fly ash could be used in cement composite production after appropriate activation of that material. This study had been conducted to assess the usefulness of mechanical and physical activation methods (grinding and sieving), as well as activation through the addition of active silica in the form of silica fume, as potential methods with which to activate biomass fly ash. Setting time, compressive strength, water absorption and bulk density tests were performed on fresh and hardened mortar. While all activation methods influenced the compressive strength development of cement mortar with fly ash, sieving of the biomass fly ash enhanced the early compressive strength of cement mortar. The use of active silica in the form of silica fume ensured higher compressive strength results than those of control specimens throughout the entire measurement period.


2014 ◽  
Vol 692 ◽  
pp. 482-485
Author(s):  
Jae Eun Jeong ◽  
Keun Hyeok Yang ◽  
In Gu Yun

This study examined initial flow and compressive strength development of polymer-modified cement mortar according to the addition of corrosion inhibitor. Test results showed that with the increase of the amount of corrosion inhibitor, the initial flow of mortars increased whereas compressive strength decreased. The strength development of mortar specimens could be reasonably predicted using the modified ACI 209 equations.


2016 ◽  
Vol 711 ◽  
pp. 232-240 ◽  
Author(s):  
Ling Shi Meng ◽  
Christopher K.Y. Leung ◽  
Geng Ying Li

This paper studies the effects of multi-walled carbon nanotubes (MWCNTs) on the mechanical properties and durability of polymer latex-modified cement mortar. Latex-modified cementitious materials possess many advantages. However, reduction of mechanical properties due to the introduction of an amorphous structure within the cement composite has limited its application. In this study, multi-walled carbon nanotubes functionalised with carboxyl group (MWCNTs-COOH), ranging from 0% to 0.15% by weight, are added into mortar modified with 0.6 wt.% polyvinyl alcohol (PVA) latex. Mechanical properties including compressive strength and flexural strength are measured. Water absorption test and rapid chloride diffusion test are performed to assess durability performance. Results indicate considerable increase of compressive strength and flexural strength, as well as improvement in durability, by the addition of MWCNTs-COOH. With Scanning Electron Microscopy conducted on both the latex solution and cement composite, the microstructural changes resulted from MWCNT addition are revealed.


2016 ◽  
Vol 857 ◽  
pp. 159-163
Author(s):  
A.A. Sinar ◽  
Z. Firuz ◽  
A.Z. Nur Hidayah ◽  
Md Akil Hazizan ◽  
H.A. Sahrim

The rigid polyurethane (PU) were produced using ionic liquid (IL) modified multi walled carbon nanotubes (MWCNTs) by reaction of palm oil based polyol (POP) with methylene diphenyl diisocyanate (MDI). The 1-butyl-3-methylimidazolium tetrafluoborate (BMIMBF4) used as IL to disperse MWCNTs in PU foam by grinding in ratio 1:3 by weight of MWCNTs to IL till black paste were obtained. The effects of different percentage of modified MWCNTs (0.0 - 3.0 %) on Polyurethane / Multi Walled Carbon Nanotubes / Ionic Liquid (PMI) foam composites were evaluated in density, morphology and compressive strength. The density were increased higher 0.0538 kg / m3 at 3.0 % PMI. The average cell size value higher without addition modified MWCNTs and scanning electron microscopy (SEM) showed inhomogenously structure with addition of modified MWCNTs. Compressive strength with 0.5 % PMI showed the highest value 1.671 MPa compared to other PMI.


Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1080 ◽  
Author(s):  
Polyxeni Dimoka ◽  
Spyridon Psarras ◽  
Christine Kostagiannakopoulou ◽  
Vassilis Kostopoulos

The present study aims to investigate the influence of multi-walled carbon nanotubes (MWCNTs) on the damage tolerance after impact (CAI) of the development of Out of Autoclave (OoA) carbon fibre reinforced polymer (CFRP) laminates. The introduction of MWCNTs into the structure of CFRPs has been succeeded by adding carbon nanotube-enriched sizing agent for the pre-treatment of the fibre preform and using an in-house developed methodology that can be easily scaled up. The modified CFRPs laminates with 1.5 wt.% MWCNTs were subjected to low velocity impact at three impact energy levels (8, 15 and 30 J) and directly compared with the unmodified laminates. In terms of the CFRPs impact performance, compressive strength of nanomodified composites was improved for all energy levels compared to the reference material. The test results obtained from C-scan analysis of nano-modified specimens showed that the delamination area after the impact is mainly reduced, without the degradation of compressive strength and stiffness, indicating a potential improvement of damage tolerance compared to the reference material. SEM analysis of fracture surfaces revealed the additional energy dissipation mechanisms; pulled-out carbon nanotubes which is the main reason for the improved damage tolerance of the multifunctional composites.


2016 ◽  
Vol 166 ◽  
pp. 45-49 ◽  
Author(s):  
Juan Bernal-Martínez ◽  
Rafael Godínez-Fernández ◽  
Manuel Roman-Aguirre ◽  
Alfredo Aguilar-Elguezabal

2015 ◽  
Vol 819 ◽  
pp. 246-250 ◽  
Author(s):  
A.A. Sinar ◽  
Zainuddin Firuz ◽  
M.A. Nur Azni ◽  
A.Z. Nur Hidayah ◽  
Md Akil Hazizan ◽  
...  

This paper describes the effect of multi walled carbon nanotubes (MWCNTs) on the properties, especially the strength properties of rigid polyurethane (PU) foams produced from palm oil based polyol (POP) and methylene diphenyl diisocyanate (MDI). The foam composites in the ratio of 1:1.1 (wt. %) mixed at speed 2000 rpm. The addition of MWCNTs into PU foam are varies from 0 wt. % to 3 wt. %. The properties evaluated were compressive strength, density and energy absorption. Compressive strength of PU foam composites with 0.5% of MWCNTs showed the highest value 1.162 MPa of compressive strength compared to other foam composites. It was proved by modeling displacement nodal magnitude using NX Software (version 8.5). The density was increased 15.69 % with addition of 0.5 % MWCNTs into the PU foam. Increasing the amount of MWCNTs in PU foam was found to improve the energy absorption from 22.89 J for pure PU to 24.53 J for foam composites with 3 % MWCNTs.


Author(s):  
Baoguo Han ◽  
Xun Yu ◽  
Jinping Ou

The carbon nanotubes (CNTs)/cement composites with different doping levels of multi-walled carbon nanotubes (MWNTs) and water/cement ratios are fabricated. By comparing the responses of electrical resistance of these CNTs/cement composites to compressive stress, the effects of MWNT doping level and water/cement ratio on the piezoresistive sensitivity of composites are investigated. Experimental results indicate that the piezoresistive sensitivities of CNTs/cement composites with 0.05 wt. %, 0.1 wt. % and 1 wt. % of MWNTs firstly increase and then decrease with the increase of CNT doping levels. The electrical resistance of CNTs/cement composites 0.6 water/cement ratio is more sensitive to compressive stress than that of composites with 0.45 water/cement ratio.


Author(s):  
Baoguo Han ◽  
Xun Yu ◽  
Jinping Ou

Sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (NaDDBS) are used as surfactants to improve the dispersion of multi-walled carbon nanotubes (MWNTs) in cement mortar and fabricate piezoresistive carbon-nanotube/cement mortar composite. The piezoresistivity of carbon-nanotube/cement mortar composite with different content levels of MWNTs and different surfactants were explored under repeated loading and impulsive loading. Experimental results indicate that NaDDBS has higher efficiency than SDS for the dispersion of MWNTs in cement mortar. The response of the electrical resistance of carbon-nanotube/cement mortar composite with NaDDBS to external force is more stable and sensitive than that of carbon-nanotube/cement mortar composite with SDS. These findings indicate that the use of NaDDBS is an effective way for improving the dispersion of MWNTs in cement-based composite and fabricating MWNTs filled cement-based composite with stable and strong piezoresistive response.


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