• flocculation in cement pastes measured through use

    Flocculation in cement pastes measured through use

    Flocculation in cement pastes measured through use of laser microscopy. In Transition from Fluid to Solid: Re-examining the Behavior of Concrete at Early Ages Technical Session at the 2009 ACI Spring Conference (259 SP ed., pp. 96-108)

  • flocculation in cement pastes measured through use

    Flocculation in Cement Pastes Measured through Use

    2009-02-01· This paper discusses the results from a study that was carried out to investigate the flocculation and floc properties in SCC cement pastes. Results show that the floc network is immediately broken down by superplasticizers and that the rate of reflocculation decreases when the water-to-cement (w/c) ratio is decreased. An increase in w/c ratio

  • flocculation in cement pastes measured through use

    Flocculation in Cement Pastes Measured through Use

    Flocculation in Cement Pastes Measured through Use of Laser Microscopy. This paper evaluates the structural build-up that occurs during the induction period is of particular interest to users of self-consolidating concrete (SCC) since it can affect the workability of concrete.

  • flocculation behavior of cement pastes containing clays

    Flocculation behavior of cement pastes containing clays

    Flocculation behavior of cement pastes containing clays and fly ash. In Transition from Fluid to Solid: Re-examining the Behavior of Concrete at Early Ages Technical Session at the 2009 ACI Spring Conference (259 SP ed., pp. 127-138)

  • cement particle flocculation and breakage monitoring

    Cement particle flocculation and breakage monitoring

    It is very difficult to directly measure the interaction of particles in a real cement paste, but the flocculation of particles in a diluted solution can be observed and statistically evaluated

  • effect of polycarboxylate ether superplasticizer (pce)

    Effect of polycarboxylate ether superplasticizer (PCE)

    One method to measure the flocculation state is by measuring the chord length distribution of particles/agglomerates. Focused Beam Reflectance Measurement (FBRM) has proved to be an efficient tool. For cement pastes, no dilution is needed, thus in-situ measurement of the chord length distribution of paste particles/agglomerates is possible.

  • flocculation behavior of cement pastes containing trid

    Flocculation Behavior of Cement Pastes Containing TRID

    Flocculation Behavior of Cement Pastes Containing Clays and Fly Ash. This paper describes how the fresh state of concrete is becoming increasingly more important in furthering the types of applications in today’s construction world.

  • cement particle flocculation and breakage monitoring

    Cement particle flocculation and breakage monitoring

    This paper proposed a LB-rheometer to measure the continuous change of the cluster size distribution and rheological properties in a cement paste suspension. Flocculation and deflocculation of cement clusters were observed using a laser backscattering instrument when cement paste was

  • effect of polycarboxylate superplasticizer on

    EFFECT OF POLYCARBOXYLATE SUPERPLASTICIZER ON

    PCS content. PCS increases the fluidity of cement pastes. The yield values range between 1.3-0.21 and 4.38-0.33 Pa for OPC and OPC+10 wt.% SF. PCS improves the fluidity of cement pastes by the dispersion of cement particles. The adsorption of PCS superplasticizer molecules on the cement particles hin-ders their flocculation as a result of the

  • international concrete abstracts portal

    International Concrete Abstracts Portal

    The effects of initial water temperature and initial cement temperature on the quick heat generation curve were evaluated. The effects of different cement chemistries were also studied. Parameters measured include maximum paste temperature at 15 minutes, cement fineness, and cement chemistry. A relationship exists between the both the initial

  • i~i':i~ii:iiiii'; university of manitoba

    i~i':i~ii:iiiii'; University of Manitoba

    The flow of cement paste was measured using apparatus specified in JIS R 5201. When the flow of cement paste was larger than the diameter of the table of apparatus, the flow was measured on an acrylic square plate of 600 mm side-length set on the table. Cement paste was prepared at water

  • (pdf) application of poly-γ-glutamic acid flocculant to

    (PDF) Application of Poly-γ-Glutamic Acid Flocculant to

    We examined the effect of poly-γ-glutamic acid flocculant (PGAF) on the removal of ultrafine cement (UFC) particles stabilized by a poly-carboxylate co-polymer, which is a superplasticizer (SP).

  • cellulose ethers and yield stress of cement pastes

    Cellulose ethers and yield stress of cement pastes

    We measure flow onset of cement pastes as a function of cellulose ether dosage. • We measure cellulose ether adsorption on cement particles. • We suggest that cellulose ethers are able to bridge cement particles. • We analyze inter-particle forces due to polymer coils stretching and desorption.

  • the origins of thixotropy of fresh cement pastes

    The origins of thixotropy of fresh cement pastes

    This is also the case of the cement paste studied in this paper as shown in Fig. 13. We plot in this figure the highest peak stress measured through the same Vane test as above for various resting times. For resting times lower than 10 min, this peak stress is measured for the soft critical strain. For larger resting times, it is measured for

  • multi-level flocculation structures of fresh cement paste

    Multi-level flocculation structures of fresh cement paste

    Multi-level flocculation structures of fresh cement paste by confocal laser scanning microscope Article (PDF Available) in Journal of Wuhan University of Technology-Mater Sci Ed 29(2):302-308

  • cement paste scientific.net

    Cement Paste Scientific.Net

    The viscosity increases of the cement pastes measured by the vibro-viscometer were more stable than those measured by the rotational viscometer. In addition, the subtle changes in the paste viscosities during the very early hydration were well detected by the vibro-viscometer. The new vibration folk technique has been shown a useful tool to characterize the microstructure changes in the early

  • surendra p. shah northwestern university

    SURENDRA P. SHAH Northwestern University

    ―Flocculation in Cement Pastes Measured through Use of Laser Microscopy,‖ ACI Committee 231 Special Publication: Transition From Fluid to Solid: Re-examining the Behavior of Concrete at Early Ages SP-259, K. Riding ed., February 2009, pp. 107-120, on disk (with R.P. Ferron and C. Negro)

  • effect of polycarboxylate ether superplasticizer (pce)

    Effect of polycarboxylate ether superplasticizer (PCE)

    Effect of polycarboxylate ether superplasticizer (PCE) on dynamic yield stress, thixotropy and flocculation state of fresh cement pastes in consideration of the Critical Micelle Concentration (CMC)

  • evaluation of an alternative flocculation system

    Evaluation of an Alternative Flocculation System

    Due to the complexity of flocculation, many fiber cement companies face difficulties in optimizing it, which leads to unpredicted production problems and lower process efficiency. This paper studies the behavior of a dual system (PFR/PEO) and compares it with two anionic polyacrylamides commonly used in this industry. The work was carried out using a focused beam reflectance measurement as a

  • flocculation and sedimentation in suspensions using

    Flocculation and sedimentation in suspensions using

    Flocculation and sedimentation in suspensions using ultrasonic wave reflection Article in The Journal of the Acoustical Society of America 129(5):2944-51 · May 2011 with 34 Reads

  • effect of polycarboxylate superplasticizer on

    EFFECT OF POLYCARBOXYLATE SUPERPLASTICIZER ON

    PCS content. PCS increases the fluidity of cement pastes. The yield values range between 1.3-0.21 and 4.38-0.33 Pa for OPC and OPC+10 wt.% SF. PCS improves the fluidity of cement pastes by the dispersion of cement particles. The adsorption of PCS superplasticizer molecules on the cement particles hin-ders their flocculation as a result of the

  • measurement of the rheological properties of high

    Measurement of the Rheological Properties of High

    1999-10-01· The rheological or flow properties of concrete in general and of high performance concrete (HPC) in particular, are important because many factors such as ease of placement, consolidation, durability, and strength depend on the flow properties.

  • physical characterization of cementitious materials

    Physical Characterization of Cementitious Materials

    Flocculation strength is various in cement paste. At a certain shear rate, some clusters, having a small flocculation strength, are broken while others, having a large flocculation strength, are not. At higher agitating speeds, more clusters are broken into small particles. On the other hand, the particles

  • evaluation of an alternative flocculation system

    Evaluation of an Alternative Flocculation System

    Effect of polyacrylamide on rheology of fresh cement pastes. Cement and Concrete Research 2015, 76, 98-106. DOI: 10.1016/j.cemconres.2015.05.012. EDUARDO LÓPEZ-MALDONADO, MERCEDES OROPEZA-GUZMÁN, ADRIÁN OCHOA-TERÁN. Improving the Effi ciency of a Coagulation-Flocculation Wastewater Treatment of the Semiconductor Industry through Zeta

  • "thixotropic behavior of cement-based materials: effect

    "Thixotropic behavior of cement-based materials: effect

    Freshly-mixed cement pastes are thixotropic materials, which become fluid when agitated but restore its structural form at rest. This is because cement pastes experience microstructure change with time due to the particles flocculation and cement hydration. The thixotropic behavior of cement-based materials is important in the modern concrete

  • cement & concrete composites academic commons

    Cement & Concrete Composites Academic Commons

    mented with a measure of the evolution of the paste’s structure. This is done through low-amplitude oscillatory shear rheometry. This methodprovides informationaboutthe viscoelastic properties of suspensions and it has been demonstrated to be applicable to fresh cement paste [20,21]. The theory is briefly explained here.

  • thixotropic behavior of cement-based materials: effect

    Thixotropic behavior of cement-based materials: effect

    Figure 4 10. Thixotropy versus time for pastes made with different types of cement 65 Figure 4 11. Yield stress versus time for pastes made with different types of cement .. 66 Figure 4 12. Viscosity versus time for pastes made with different types of cement .. 66 Figure 4 13. Bivariate Fit of Thixotropy by Time for Actigel

  • study of the mechanisms underlying the fresh-state

    Study of the mechanisms underlying the fresh-state

    Concrete Cement paste Nanoclay Rheology Fresh-state Formwork pressure Flocculation abstract The fresh-state properties of concrete can be tailored to meet the needs of specific applications, such as reduced formwork pressure for self-consolidating concrete (SCC), which requires high flowability, and

  • flocculation and sedimentation in suspensions using

    Flocculation and sedimentation in suspensions using

    2011-05-10· This work was undertaken to help understand and interpret the ultrasonic wave reflection response of Portland cement paste as it transforms from a fluid-like suspension to a solid in the first hours after mixing. A high impact polystyrene buffer (delay line) was used to measure small changes in the P- and S-wave reflection coefficients.

  • flocculation

    Flocculation

    Flocculation, in the field of chemistry, is a process in which colloids come out of suspension in the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution .

  • water free full-text application of poly-γ-glutamic

    Water Free Full-Text Application of Poly-γ-Glutamic

    The ionic composition and concentration of the pore water in cement pastes vary depending on the cement type and extraction pressure [17,18]. In this experiment, Na +, K +, Ca 2+, Cl −, and SO 4 2− were measured as main ions based on the results [19,20,21] of the bulk concentration of the cement

  • asce journals of materials in civil concrete.nist.gov

    ASCE Journals of Materials in Civil concrete.nist.gov

    fraction. However, a simple parametric study in 100 % ordinary portland cement pastes in which water content (water-to-cement ratio) is varied indicates that the relation between resistance trends and subsequent setting times is strongly dependent on the water content, as is also the case for the thermal measurements. This suggests that

  • influence of clays on the rheology of cement pastes

    Influence of Clays on the Rheology of Cement Pastes

    Influence of Clays on the Rheology of Cement Pastes. The fresh state of concrete is becoming increasingly important in furthering the types of applications of today's construction world. Processing techniques have resulted in technologies such as self-consolidating concrete and depend on the microstructural changes that take place during and

  • enhancing thixotropy of fresh cement pastes with

    Enhancing thixotropy of fresh cement pastes with

    Nanoclay, a thermal treated, purified attapulgite clay, has been used to increase thixotropy. However, the effect of nanoclay in presence of water reducing agent, such as PCE, on rheology, and the compatibility between nanoclay and PCE have not been well studied. The dynamic yield stress, thixotropic index, characteristic time, and microstructure of fresh cement pastes with combination of

  • effect of w/c ratio on durability and porosity in cement

    Effect of W/C Ratio on Durability and Porosity in Cement

    Water is often added to concrete placing for easy workability and finishability in construction site. The additional mixing water can help easy mixing and workability but causes increased porosity, which yields degradation of durability and structural performances. In this paper, cement mortar samples with 0.45 of W/C (water to cement) ratio are prepared for control case and durability

  • cement hydration: building bridges and dams at the

    Cement Hydration: Building Bridges and Dams at the

    Thus, the initial water-to-cement ratio (w/c),particle size distribution,and dispersion/flocculation state of the particles all exert major influences not only on the developed microstructure (through and beyond setting) but also on the hydration kinetics. The bridging process can be conveniently explored via a coordinated experimental and

  • effects of cement particle size distribution

    Effects of Cement Particle Size Distribution

    EFFECTS OF CEMENT PARTICLE SIZE DISTRIBUTION ON PERFORMANCE PROPERTIES OF PORTLAND CEMENT-BASED MATERIALS D.P. Bentz a, E.J. Garboczi a, C.J. Haecker b, and O.M. Jensen c a Building and Fire Research Laboratory Building 226 Room B-350 National Institute of Standards and Technology

  • online civil engineering: carbonation depth

    ONLINE CIVIL ENGINEERING: CARBONATION DEPTH

    If the test is to be done in a drilled hole, the dust is first removed from the hole using an air brush and again the depth of the uncoloured layer measured at 4 or 8 positions and the average taken. If the concrete still retains its alkaline characteristic the colour of the concrete will change to purple. If carbonation has taken place the pH

  • application of ultrasonic p-wave reflection to measure

    Application of ultrasonic P-wave reflection to measure

    Also, the P-wave reflection coefficient showed higher values for pastes with lower water to cement ratios, which are primarily attributed to the higher density of low w/c pastes, and similar effects with addition of fly ash and entrained air. Partial debonding between paste and buffer was observed in most pastes at a time that coincided with final set as measured using S-waves; and the

  • coagulation and flocculation

    COAGULATION and FLOCCULATION

    coagulation and flocculation effect removal in the area of water treatment alone, one may say that these processes are veritable wovk-hovaea of whichever overall treatment scheme is applied. Such a diversity of material, ranging from clay particles through various biological forms to substances in

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