Nanofibrillated cellulose as nanoreinforcement in Portland cement: Thermal, mechanical and microstructural properties

2016 ◽  
Vol 51 (17) ◽  
pp. 2491-2503 ◽  
Author(s):  
Roukaya Mejdoub ◽  
Halim Hammi ◽  
Joan Josep Suñol ◽  
Mohamed Khitouni ◽  
Adel M‘nif ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Cement Hydration ◽  
Coefficient Of Thermal Expansion ◽  
Nanofibrillated Cellulose ◽  
Partial Replacement ◽  
Cellulose Content ◽  
Cement Pastes ◽  
Eucalyptus Pulp ◽  
Reinforced Cement ◽  
Mechanical And Microstructural Properties

Nanofibrillated cellulose from eucalyptus pulp, produced by high-pressure homogenization, was used as cement partial replacement for cement paste at a content ranging from 0% to 0.5% by weight of cement. The effect of the content of nanofibrillated cellulose on porosity, thermal properties, compressive strength and degree of cement hydration was investigated. Results have shown an improvement in the compressive strength by more than 50% with 0.3 wt% of added nanofibrillated cellulose. The porosity was reduced by nanofibrillated cellulose addition, and the greatest result was achieved with mixture incorporating 0.3 wt% nanofibrillated cellulose. The coefficient of thermal expansion and the thermal conductivity measurements, relative to nanofibrillated cellulose-reinforced cement pastes, have pointed out the reinforcement effectiveness of nanofibrillated cellulose. The degree of cement hydration has increased with nanofibrillated cellulose content. This trend was confirmed by X-ray diffraction and Fourier Transform Infrared spectroscopy. These analyses have revealed that the presence of nanofibrillated cellulose promoted the hydration of cement, by producing more portlandite and calcium silicate gel, which is likely the main reason accounting for the strong enhancement in the compressive strength.

High Volume Slag and Slag-Fly Ash Blended Cement Pastes Containing Nano Silica

2019 ◽  
Vol 967 ◽  
pp. 205-213
Author(s):  
Faiz U.A. Shaikh ◽  
Anwar Hosan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Cement Paste ◽  
Ordinary Portland Cement ◽  
Blended Cement ◽  
High Volume ◽  
Ash Content ◽  
Partial Replacement ◽  
Nano Silica ◽  
Cement Pastes

This paper presents the effect of nanosilica (NS) on compressive strength and microstructure of cement paste containing high volume slag and high volume slag-fly ash blend as partial replacement of ordinary Portland cement (OPC). Results show that high volume slag (HVS) cement paste containing 60% slag exhibited about 4% higher compressive strength than control cement paste, while the HVS cement paste containing 70% slag maintained the similar compressive strength to control cement paste. However, about 9% and 37% reduction in compressive strength in HVS cement pastes is observed due to use of 80% and 90% slag, respectively. The high volume slag-fly ash (HVSFA) cement pastes containing total slag and fly ash content of 60% exhibited about 5%-16% higher compressive strength than control cement paste. However, significant reduction in compressive strength is observed in higher slag-fly ash blends with increasing in fly ash contents. Results also show that the addition of 1-4% NS improves the compressive strength of HVS cement paste containing 70% slag by about 9-24%. However, at higher slag contents of 80% and 90% this improvement is even higher e.g. 11-29% and 17-41%, respectively. The NS addition also improves the compressive strength by about 1-59% and 5-21% in high volume slag-fly ash cement pastes containing 21% fly ash+49%slag and 24% fly ash+56%slag, respectively. The thermogravimetric analysis (TGA) results confirm the reduction of calcium hydroxide (CH) in HVS/HVSFA pastes containing NS indicating the formation of additional calcium silicate hydrate (CSH) gels in the system. By combining slag, fly ash and NS in high volumes e.g. 70-80%, the carbon footprint of cement paste is reduced by 66-76% while maintains the similar compressive strength of control cement paste. Keywords: high volume slag, nanosilica, compressive strength, TGA, high volume slag-fly ash blend, CO2 emission.

scholarly journals Effect of basalt powder addition on properties of mortar

2019 ◽  
Vol 262 ◽  
pp. 06002 ◽  
Author(s):  
Magdalena Dobiszewska ◽  
Waldemar Pichór ◽  
Paulina Szołdra
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Beneficial Effect ◽  
Cement Paste ◽  
Cement Hydration ◽  
Asphalt Mixture ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Freeze Resistance ◽  
Powder Addition

The study evaluates the use of waste basalt powder as a replacement of cement to enhance hydration of cement and mortar properties. The basalt powder is a waste resulting from preparation of aggregate used in asphalt mixture production. Previous studies have shown that analysed waste used as a fine aggregate replacement has a beneficial effect on some properties of mortar and concrete, i.e. compressive strength, flexural strength and freeze resistance. The present study shows the results of the research concerning the modification of cement paste and mortar with basalt powder. The modification consists in adding the powder waste as a partial replacement of cement. The percentages of basalt powder in this research are 0-40% and 0-20% by mass of cement in the pastes and mortars respectively. The experiments were carried out to determine the influence of basalt powder on cement hydration, as well as compressive and flexural strength. Results indicate that addition of basalt powder as a replacement of cement leads to deterioration of compressive strength. The flexural strength of mortar is improved in some cases. Waste basalt powder only slightly influences the cement hydration.

Influence of Physicochemical Properties of Sugarcane Bagasse Ash (SCBA) in Portland Cement Hydration

2018 ◽  
Vol 765 ◽  
pp. 324-328
Author(s):  
Tiago Assunção Santos ◽  
José da Silva Andrade Neto ◽  
Vitor Souza Santos ◽  
Daniel Véras Ribeiro
Keyword(s):  
Portland Cement ◽  
Sugarcane Bagasse ◽  
Cement Hydration ◽  
New Technologies ◽  
Pozzolanic Reaction ◽  
Cement Industry ◽  
Partial Replacement ◽  
Cement Pastes ◽  
Sugarcane Bagasse Ash ◽  
Portland Cement Hydration

Due to the concern with the environmental impacts caused by the gases emitted by the cement industry and by the inadequate disposal of wastes generated in the sugar-alcohol industry, such as sugarcane bagasse ash (SCBA), a search for the development of new technologies, which are less aggressive to the environment and that propose feasible alternatives, began in order to reuse these wastes properly. Among these alternatives is the reuse of SCBA as partial replacement to cement or as addition to cementitious matrices. In this way, the present research has the objective of analyzing the influence of SCBA obtained by the calcination of sugarcane bagasse (SCB), at 600°C, in the process of Portland cement hydration. Initially, the SCBA was characterized physically, chemically and mineralogically, and then cement pastes with 20% and 35% substitution contents were elaborated, besides the reference paste, which were analyzed through X-ray diffraction (XRD) and thermogravimetric (TG) techniques. The results obtained show that there is a consumption of portlandite as a consequence of the use of SCBA, evidencing the pozolanicity of these ashes. In the pastes with 35% substitution content, there was an intense consumption of the portlandite, indicating, in this proportion, the pozzolanic reaction was more intense.

The Effect of Micronized Waste Marble Powder as Partial Replacement for Cement on Resulting Mechanical Properties of Cement Pastes

2017 ◽  
Vol 1144 ◽  
pp. 54-58
Author(s):  
Zdeněk Prošek ◽  
Karel Šeps ◽  
Jaroslav Topič
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Reference Material ◽  
Dynamic Modulus ◽  
Blended Cement ◽  
Partial Replacement ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Cement Pastes ◽  
Marble Powder

This article was focused on the influence of the micronized waste marble powder on mechanical properties of cement pastes. Resulting blended cement was composed of Portland cement CEM I 42.5 R and micronized marble powder with different percentage amounts (0 wt. %, 5 wt. %, 10 wt. % and 15 wt. %). Testing was carried at prismatic samples of dimension 40 × 40 × 160 mm. The investigated mechanical properties were dynamic modulus of elasticity, dynamic shear modulus, flexural strength and compressive strength for the 28 days old samples. The results obtained from these materials were compared with reference material.

Compressive Strength and Microstructure of Multi-Wall Carbon Nanotubes Reinforced Cement Composites

2012 ◽  
Vol 450-451 ◽  
pp. 594-599
Author(s):  
Jin Tao Liu ◽  
Dong Ming Yan ◽  
Shi Lang Xu
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Carbon Nanotube ◽  
Microscopic Analysis ◽  
Cement Composites ◽  
Cement Pastes ◽  
Multi Wall Carbon Nanotubes ◽  
Multi Walled Carbon Nanotubes ◽  
Reinforced Cement ◽  
Walled Carbon Nanotubes

Advancement in the study of carbon nanotube has enabled its application in civil engineering as constitutive materials or additives. In this study, the availability of applying multi-walled carbon nanotube to improve the characteristics of cement composites was investigated with experiments on more than 30 specimens. The multi-walled carbon nanotubes (MWCNTs) were effectively dispersed in the water with surfactant, which can keep stable for over 3 months. Specimens with MWCNTs of 0.025%, 0.05% and 0.1% of cement (by weight) were tested with a loading machine and then analyzed with a SEM. It was found that the compressive strength of the samples increased with the increasing MWCNTs, it can improve the 7-day compressive strength by 22% . Microscopic analysis (SEM) revealed that carbon nanotubes were surrounded with hydration products. The bridging and debonding of carbon nanotubes in cement pastes was observed as well.

scholarly journals The effects of seawater on the hydration, microstructure and strength development of Portland cement pastes incorporating colloidal silica

2019 ◽  
Vol 10 (8) ◽  
pp. 2627-2638 ◽  
Author(s):  
Pawel Sikora ◽  
Krzysztof Cendrowski ◽  
Mohamed Abd Elrahman ◽  
Sang-Yeop Chung ◽  
Ewa Mijowska ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Synergistic Effect ◽  
Portland Cement ◽  
Colloidal Silica ◽  
Cement Hydration ◽  
Pozzolanic Reaction ◽  
Strength Development ◽  
Hydration Kinetics ◽  
Cement Pastes ◽  
Noticeable Improvement

AbstractThis contribution investigates the effects of seawater and colloidal silica (NS) in the amounts of 1, 3 and 5 wt%, respectively, on the hydration, strength development and microstructural properties of Portland cement pastes. The data reveal that seawater has an accelerating effect on cement hydration and thus a significant contribution to early strength development was observed. The beneficial effect of seawater was reflected in an improvement in compressive strength for up to 14 days of hydration, while in the 28 days compressive strength values were comparable to that of cement pastes produced with demineralized water. The combination of seawater and NS significantly promotes cement hydration kinetics due to a synergistic effect, resulting in higher calcium hydroxide (CH) production. NS can thus react with the available CH through the pozzolanic reaction and produce more calcium silicate hydrate (C-S-H) gel. A noticeable improvement of strength development, as the result of the synergistic effect of NS and seawater, was therefore observed. In addition, mercury intrusion porosimetry (MIP) tests confirmed significant improvements in microstructure when NS and seawater were combined, resulting in the production of a more compact and dense hardened paste structure. The optimal amount of NS to be mixed with seawater, was found to be 3 wt% of cement.

scholarly journals Influence of stone cutting waste and ground waste clay brick on the hydration and packing density of cement pastes

2013 ◽  
Vol 6 (4) ◽  
pp. 661-680 ◽  
Author(s):  
C. A. A. Rocha ◽  
G. C. Cordeiro ◽  
R. D. Toledo Filho
Keyword(s):  
Compressive Strength ◽  
Binary Mixture ◽  
Packing Density ◽  
Cement Hydration ◽  
Clay Brick ◽  
Cement Pastes ◽  
Strength Tests ◽  
Stone Cutting ◽  
Small Acceleration ◽  
Compressible Packing Model

The present work aims to study the replacement of Portland cement (PC) by stone cutting waste (SW) and ground waste clay brick (BW) in binary and ternary pastes. Thermogravimetry and differential thermal analysis tests were carried out at various ages in order to investigate the development of the cement hydration reactions in the presence of those wastes. The packing density was calculated in accordance with the Compressible Packing Model to understand the physical effect of those wastes. Compressive strength tests were also performed and the results were related to hydration and packing. Considering the substitution levels studied, the results indicated that the use of SW in the binary mixture accelerated the hydration reactions, and the particles packing density and compressive strength were maintained. The use of BW in the binary mixture caused a small acceleration in the hydration reactions and there was an indication of pozzolanic activity, although the compressive strength was reduced in comparison with the reference paste. In the ternary mixture, the combined effect of both wastes resulted in the maintenance of compressive strength for cement replacement content of 30%.

Effects of Fineness on Activity Character of Fly Ash

2011 ◽  
Vol 266 ◽  
pp. 114-117
Author(s):  
Zhong Tao Luo ◽  
Bao Guo Ma ◽  
Jiu Jun Yang ◽  
Jun Xia Liu
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Cement Hydration ◽  
Chemical Activation ◽  
Cement Pastes ◽  
Starting Point ◽  
Aggregate Effect ◽  
Granule Morphology ◽  
Morphology Effect ◽  
Micro Analysis

The hydrated character of cement paste with fly ash was studied, through the methods of compressive strength, non-evaporable water content, reaction degree of fly ash and micro-analysis. The results indicated that the chemical activity of fly ash was an accumulative change process under this test condition. The starting point of chemical reaction of fly ash was nearby 28 days. In front of 28 days, the chemical activation of fly ash was not wakened, and the compressive strength of cement pastes with fly ash at this age was mainly from multiplex effects of cement hydration and the micro-aggregate effect, granule morphology effect and pozzolanic effect of fly ash.

Effect of Plasticizing Admixtures on the Development of Hydration Temperatures and the Properties of Cement Pastes

2018 ◽  
Vol 761 ◽  
pp. 116-119
Author(s):  
Martin Sedlmajer ◽  
Jiri Zach ◽  
Jitka Hroudova
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Hydration ◽  
Hydration Heat ◽  
Close Monitoring ◽  
Cement Pastes ◽  
Concrete Members

The hydration of cement is a very intricate process. A great amount of heat is generated during the reaction, which requires close monitoring especially in large concrete members. Modified cement pastes are simpler systems and can be easily used to observe the effect of plasticizing admixtures on the development of temperatures during cement hydration as well as its rheology and mechanical properties. Knowledge of the development of hydration temperatures can be of assistance in deliberate regulation of cement hydration and the generation of hydration heat. The paper describes what influence different amounts of different plasticizers have on the properties of cement pastes, with added focus on the development of their hydration temperatures, rheology and compressive strength.

scholarly journals Effects of Quartz Powder on the Microstructure and Key Properties of Cement Paste

2018 ◽  
Vol 10 (10) ◽  
pp. 3369 ◽  
Author(s):  
Run-Sheng Lin ◽  
Xiao-Yong Wang ◽  
Gui-Yu Zhang
Keyword(s):  
Compressive Strength ◽  
Linear Relationship ◽  
Cement Hydration ◽  
Isothermal Calorimetry ◽  
Bound Water ◽  
Heat Of Hydration ◽  
Crystal Nucleation ◽  
Partial Replacement ◽  
Quartz Powder ◽  
X Ray

This paper compares the effects of the water-to-binder (w/b) ratio and quartz contents on the properties of cement–quartz paste. The w/b ratios of the paste mixtures specimens are 0.5 and 0.2, and the quartz powder contents are 0, 10, and 20%. At the age of 1, 3, 7, and 28 days, compressive strength test, X-ray fluorescence (XRF) spectroscopy, X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), isothermal calorimetry, and thermogravimetric (TG) analysis were performed. The experimental results show that the quartz powder mainly has the dilution effect and crystal nucleation effect on cement hydration, and the addition of quartz powder does not change the type of hydration product. The effect of quartz powder on cement hydration is closely related to the w/b ratio. In the case of a low w/b ratio of 0.2, the addition of quartz powder did not impair the compressive strength of paste. For different w/b ratios (0.5 and 0.2) and various quartz powder contents (0, 10, and 20%) at different ages (1, 3, 7, and 28 days), there is a uniform linear relationship between strength and porosity. Similarly, there is a uniform linear relationship between chemically bound water and calcium hydroxide, between heat of hydration and compressive strength, and between chemically bound water and compressive strength. At the same time, the effect of the partial replacement of cement by quartz powder on sustainability is considered in this paper.

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