scholarly journals Studying the impact of admixtures chemical structure on the rheological properties of silica-fume blended cement pastes using various rheological models

2021 ◽  
Author(s):  
A.O. Habib ◽  
I. Aiad ◽  
F.I. El-Hosiny ◽  
Alaa Mohsen
Keyword(s):  
Rheological Properties ◽  
Silica Fume ◽  
Chemical Structure ◽  
Blended Cement ◽  
Rheological Models ◽  
Cement Pastes ◽  
The Impact

Shrinkage of Blended Cement Pastes with Mineral Additions

2013 ◽  
Vol 539 ◽  
pp. 55-59
Author(s):  
Yi Chen ◽  
Wu Yao ◽  
Dan Jin
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Mercury Intrusion Porosimetry ◽  
Construction Materials ◽  
Blended Cement ◽  
Cement Pastes ◽  
Mercury Intrusion ◽  
Mineral Additions ◽  
By Products

Mineral additions such as fly ash and silica fume are industrial by products, and play an important role in properties improvement for construction materials. In this work, the shrinkage of cement paste blended with fly ash and silica fume by different substitute ratio was studied. Pore structures of specimens at different ages were determined by mercury intrusion porosimetry (MIP) and shrinkage deformation was measured by standard shrinkage tests. The effects of mineral addtions on shrinkage were discussed. The results show that the fly ash was significantly effective on shrinkage at early ages. Based on the research, several suitable advices were offered to optimize the performances of materials and reduce the shrinkage.

The impact of vermiculite residual fines in the rheological properties of cement pastes formulated with different waste contents

2019 ◽  
Vol 170 ◽  
pp. 97-105 ◽  
Author(s):  
Roberto Antonio Rojas-Ramírez ◽  
Marcel Hark Maciel ◽  
Roberto Cesar de Oliveira Romano ◽  
Rafael Giuliano Pileggi ◽  
Antonio Carlos Vieira Coelho
Keyword(s):  
Rheological Properties ◽  
Cement Pastes ◽  
The Impact

The mechanism of cesium immobilization in densified silica-fume blended cement pastes

2008 ◽  
Vol 38 (5) ◽  
pp. 667-674 ◽  
Author(s):  
G. Bar-Nes ◽  
A. Katz ◽  
Y. Peled ◽  
Y. Zeiri
Keyword(s):  
Silica Fume ◽  
Blended Cement ◽  
Cement Pastes ◽  
Cesium Immobilization

Dry Shrinkage and Compressive Strength of Blended Cement Pastes with Fly Ash and Silica Fume

2012 ◽  
Vol 535-537 ◽  
pp. 1735-1738 ◽  
Author(s):  
Yan Li ◽  
Dao Sheng Sun ◽  
Xiu Sheng Wu ◽  
Ai Guo Wang ◽  
Wei Xu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Blended Cement ◽  
Drying Shrinkage ◽  
Cementitious Material ◽  
Strength Increase ◽  
Cement Pastes ◽  
Dry Shrinkage

This paper reports the drying shrinkage and compressive strength results of cement pastes with fly ash and silica fume. In this study, Portland cement (PC) was used as the basic cementitious material. Fly ash (FA) and silica fume (SF) were used as cement replacement materials at levels of 0%, 5%, 10%, and 15% , 40%, 35%, 25%, and 15% by weight of the total cementitious material, respectively. The water/cement (PC + FA + SF) ratios (w/c) was 0.28 by weight. The samples produced from fresh pastes were demoulded after a day; then they were cured at 20 ±1°C with 50 ± 3% relative humidity (RH) until the samples were used for drying shrinkage and compressive strength measurement at various ages. The results show that drying shrinkage and compressive strength increase with increasing SF content, and the optimum composition of blended cement pastes is the cement paste with 30% fly ash and 10% silica fume, which possesses lower drying shrinkage values than that of plain cement paste and higher early age strength than that of blended cement pastes with fly ash. Furthermore, a linear relationship is established between compressive strength and drying shrinkage. By comparing the development of compressive strength and the drying shrinkage deformations, it appears possible to predict the drying shrinkage according to the acquired compressive strength.

scholarly journals Analysis of the Effect of Various Types of Limestone as a Main Constituent of Cement on the Chosen Properties of Cement Pastes and Mortars

2019 ◽  
Vol 65 (3) ◽  
pp. 75-86
Author(s):  
J. Gołaszewski ◽  
G. Cygan ◽  
M. Gołaszewska
Keyword(s):  
Compressive Strength ◽  
Rheological Properties ◽  
Yield Stress ◽  
Drying Shrinkage ◽  
Plastic Viscosity ◽  
Main Constituent ◽  
Cement Pastes ◽  
Mortar Strength ◽  
The Impact

AbstractThe article is an attempt to compare the impact of the use of various types of limestone as the main constituent of cement on selected mortar properties. Four different limestones were added in amount of 15, 30, 40% to CEM I 42.5 R to obtain limestone cemens. Rheological properties (yield stress, plastic viscosity) of fresh mortar, tensile and compressive mortar strength, early shrinkage, and drying shrinkage were tested. Obtained results indicate that both tensile and compressive strength decreases with the increase of the limestone content in cement. Limestone can worsen or improve workability, depending on distribution of limestone grains. The addition of limestone increases the early shrinkage, but reduces the shrinkage after 28 days. Studies show that the granulation of limestone plays an important role in determining the influence of limestone on mortar properties.

scholarly journals Investigation of Rheological Properties of Blended Cement Pastes Using Rotational Viscometer and Dynamic Shear Rheometer

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Yoo Jae Kim ◽  
Bum-Yean Cho ◽  
Soon-Jae Lee ◽  
Jiong Hu ◽  
James W. Wilde
Keyword(s):  
Rheological Properties ◽  
Flow Behavior ◽  
Blended Cement ◽  
Mineral Admixture ◽  
Dynamic Shear ◽  
Dynamic Shear Rheometer ◽  
Rotational Viscometer ◽  
Cement Pastes ◽  
And Control ◽  
Total Shear

To successfully process concrete, it is necessary to predict and control its flow behavior. However, the workability of concrete is not completely measured or specified by current standard tests. Furthermore, it is only with a clear picture of cement hydration and setting that full prediction and control of concrete performance can be generalized. In order to investigate the rheological properties of blended cement pastes, a rotational viscometer (RV) was used to determine the flow characteristics of ordinary and blended pastes to provide assurance that it can be pumped and handled. Additionally, a dynamic shear rheometer (DSR) was used to characterize both the viscous and elastic components of pastes. Ordinary Portland cement paste and blended pastes (slag, fly ash, and silica fume) were investigated in this study. The stress and strain of the blended specimens were measured by the DSR, which characterizes both viscous and elastic behaviors by measuring the complex shear modulus (the ratio of total shear stress to total shear strain) and phase angle (an indicator of the relative amounts of recoverable and nonrecoverable deformation) of materials. Cement pastes generally exhibit different rheological behaviors with respect to age, mineral admixture type, and cement replacement level.

scholarly journals Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement Paste

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2683
Author(s):  
Elżbieta Janowska-Renkas
Keyword(s):  
Chemical Structure ◽  
Side Chains ◽  
Test Results ◽  
High Concentration ◽  
Ion Content ◽  
Cement Pastes ◽  
Carboxylate Groups ◽  
Paste Viscosity ◽  
The Impact ◽  
Derivatives Of

The paper presents test results of the impact of sulphate ions from calcium sulphates: Hemihydrate, dihydrate and anhydrite, on rheological properties and hydration heat of cement pastes with, and without, superplasticizers, derivatives of maleic (SP-2) and acrylic (SP-1) acids. It is demonstrated that cement pastes fluidity depends on superplasticizer chemical structure, and its effect is expressed by a hydrophilic coefficient. As maleic superplasticizers have flexible comb-like structure composed of a shorter backbone chain containing COO− carboxylate groups and very long side chains, cement pastes showed higher fluidity than with acrylic superplasticizer with ladder-like structure, longer backbone chains with shorter side chains. SP-1 showing lower hydrophilicity coefficient and fewer COO− groups was found to be less sensitive to increased sulphate ion content in pastes. However, with SP-2 with higher hydrophilicity, a gradual fluidity loss (increased paste viscosity) was observed. Plastic viscosity was approximately at the same level in SP-1-containing pastes. Tests showed that sulphates definitely changed polycarboxylate superplasticizers performance. A high concentration of sulphate ions reduced maleic superplasticizer efficiency. Under these conditions, SP-1 is more effective and therefore more suitable for fluidity of pastes containing higher SO42− ions content. Thus, sulphate ions concentration in the paste should be considered when selecting superplasticizer.

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