Influence of mixing process on mortars rheological behavior through rotational rheometry

França, Marylinda Santos de; Cazacliu, Bogdan; Cardoso, F. A.; Pileggi, Rafael Giuliano

doi:10.1016/j.conbuildmat.2019.06.213

Cited by 21 publications

(9 citation statements)

References 37 publications

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“…In (a), results for all mortars and table with yield torque and plastic viscosity (* equivalent to plastic viscosity based on torque vs. rotation curves [74]); in (b), linear fits for CTA and SLM mortars with zoom in values of torque up to 0.5 N.m and rotation speed up to 100 rpm. All tests were performed in a rotational rheometer with planetary setup and attritor impeller, step-based shear cycle up to 190 rpm [75] (data from [76][77][78]). a self-leveling mortar (or concrete) must be characterized by sufficiently low yield stress that allows the material to flow under its own weight [72,73].…”

Section: Raw Materials Of Ternary System Opc-cac-casomentioning

confidence: 99%

Ternary system Portland cement-calcium aluminate cement-calcium sulfate applied to self-leveling mortar: a literature review

2021

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The modernization of building systems is increasingly demanding products that improve efficiency during their processing. The development of self-leveling mortars for the regularization of flooring is a consequence of this evolution. The high contents of binder and water to obtain self-flowing property, plus the application of thin layers over large areas, make this type of mortar susceptible to high shrinkage levels. Thus, the ternary system Portland cement-calcium aluminate cement-calcium sulfate (OPC-CAC-CaSO 4) is a viable solution for shrinkage compensation. The expansion mechanism based on ettringite formation aims to prevent the mortar from cracking. Considering its complexity and that international literature is still limited (while Brazilian is null), this article presents a literature review that covers diverse aspects related to the application of the system OPC-CAC-CaSO 4. The influence of raw materials and mix proportions on rheological behavior, reaction kinetics, development of strength, and length change are discussed.

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Section: Raw Materials Of Ternary System Opc-cac-casomentioning

confidence: 99%

Ternary system Portland cement-calcium aluminate cement-calcium sulfate applied to self-leveling mortar: a literature review

2021

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“…Mixing time can be reduced with high mixing speed but in case of selfcompacting concrete, excessive speed has a large influence on its workability [23]. Bad mixing is the result of too short time or slow water loading rate [24]. Bad mixing has bad effects on the mechanical properties of mortars.…”

Section: Literature Reviewmentioning

confidence: 99%

Effect of Low Mixing Speed on the Properties of Prolonged Mixed Concrete

El-Motaal¹,

Abdel-Reheem²,

Mahdy³

2020

Civ Eng J

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The mixing process of concrete consists of dispersing the constituent ingredients (i.e. cement, admixtures, sand, and gravel) in water to homogeneous and solid product. The properties of the final product depend on mixing parameters such as mixing time and mixing speed. Ready Mixed Concrete (RMC) should be mixed for a long time with limited speed until delivered to the working site. This long time depends on long transport distances and traffic conditions. The present study investigated the effects of long mixing time on the properties of concrete without any change in its proportions during the mixing process and the effects of using the chemical admixtures: super plasticizers and retarders on its effectiveness, using a drum batch mixer. It has two directions of rotation: one for mixing concrete and the other for discharging it. This research identified concrete mixtures with local available materials i.e. cement, sand as fine aggregates, dolomite as coarse aggregates, water and chemical admixtures. Mixtures were prepared with the same cement and water content with constant sand to dolomite ratio with different dosages of chemical admixtures. Chemical admixtures were used to keep concrete flow during mixing. Mixtures were prepared with low mixing speed 1rpm for identified long mixing times more than 90 minutes from adding water to other components Slump and compressive tests were used as measurement tools of fresh and hardened concrete Retempering with extra water or chemical admixtures was prevented through mixing, so mixtures were extracted without target slump value. Findings showed that low mixing speeds made mixtures more effective for long times, the exceeding mixing time led to minimize water to cement ratio due to reduction of water content, and there was an inverse relationship between slump flow and compressive strength in case of no re-tempering. Therefore, slump flow of mixtures decreased by time, but on the other hand, compressive strength enhanced i.e. stiffening took place. The present study proved that the properties of the final product depends on mixing parameters such as mixing time and mixing speed, and that Ready Mixed Concrete (RMC) would be more effective if mixed for a long time with limited speed until transported to the work site. In addition, chemical admixtures with prolonged mixed concrete should be used to improve workability rather than compressive strength.

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“…It is important to control particle homogenisation and dispersion in mixes, but there are no commonly used methods to carry out such studies. Studying the mixing process would be more effective with the help of various rheological characteristics [ 25 , 26 , 27 , 28 , 29 ].…”

Section: Introductionmentioning

confidence: 99%

Modelling the Influence of Composition on the Properties of Lightweight Plaster Mortar and Multicriteria Optimisation

et al. 2023

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The influence of the components of plaster mortars on their properties is considered in a lot of studies at a qualitative level without searching for optimal compositions of these multicomponent composite materials. The purpose of this study was to obtain the experimental–statistical models based on the results of the designed experiment, allowing the influence of light fillers and polymer admixtures on the properties of the mortars to be evaluated and analysed; the compositions complying with specified requirements and compromised optimally by a number of properties should be found. The quantities of fine limestone and perlite as well as of the hydroxyethyl methyl cellulose and dispersible polymer were varied in the experiment. The effective viscosity and thixotropy of the mix, compression, tensile, adhesive strength, frost resistance, and density of hardened mortars were determined for 18 compositions according to the experiment design. The obtained models have allowed the individual and synergetic effects of mix components to be evaluated. The fine perlite has turned out to have the greatest positive effect on the properties. This porous filler increases the strength while decreasing the density of the mortars. It is shown how the composition complying with specified requirements—and the best based on several properties—has been found.

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Influence of mixing process on mortars rheological behavior through rotational rheometry

Cited by 21 publications

References 37 publications

Ternary system Portland cement-calcium aluminate cement-calcium sulfate applied to self-leveling mortar: a literature review

Ternary system Portland cement-calcium aluminate cement-calcium sulfate applied to self-leveling mortar: a literature review

Effect of Low Mixing Speed on the Properties of Prolonged Mixed Concrete

Modelling the Influence of Composition on the Properties of Lightweight Plaster Mortar and Multicriteria Optimisation

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