Experimental Developments of the Squeeze Flow Test for Mortars

Cardoso, F. A.; Grandes, Franco A.; Sakano, Victor Keniti; Rego, Andressa C.A.; Lofrano, Fábio Cunha; John, Vanderley Moacyr; Pileggi, Rafael Giuliano

doi:10.1007/978-3-030-22566-7_22

Cited by 5 publications

(5 citation statements)

References 4 publications

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“…The rheological parameters viscosity (η, in Pa.s) and yield stress (τ0, in Pa) were estimated using respectively Equations 1 and 2, proposed by Meeten [34]. Although the actual yield stress is measured by rotational rheometry [40], similar approaches have been successfully used to estimate the yield stress of cement-based materials [37], [38], [41].…”

Section: Testing Methodsmentioning

confidence: 99%

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Effect of Carbon Nanotubes (CNTs) aspect ratio on the rheology, thermal conductivity and mechanical performance of Portland cement paste

Batiston

Gleize

Mezzomo

et al. 2021

Rev. IBRACON Estrut. Mater.

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Carbon nanotubes (CNTs) are potential candidates to enhance the heat balance of concrete, reducing internal stresses caused by differential heating in massive concrete elements. The higher the aspect ratio (AR) and content of CNTs, the greater the expected thermal conductivity (TC). However, high AR may impair the proper dispersion of CNTs in cementitious matrix, potentially harming the workability and mechanical strength of the composite. This work evaluated the effect of the AR (35, 250, 900, and 3500) and content (0.05% and 0.10%) of CNTs on the TC, rheology (squeeze flow), and mechanical strength of cement paste. Results showed that 0.05% CNT increased the TC of paste by up to 15% for AR of 250, but further increasing AR progressively reduced the TC of the composite. In turn, 0.10% CNT incorporation did not result in significant TC gains. The yield stress and viscosity of the mixes progressively increased as CNTs content and AR increased, by up to 119% compared with plain cement paste. No significant differences were observed in 28-day compressive strength with 0.05% CNT incorporation, while 0.10% CNT led to slight strength reductions for some mixes. Regarding flexural strength, 0.05% incorporation of either CNT decreased the strength of the mixes while 0.10% incorporation generally compensated this reduction, except for the lowest aspect ratio. Overall, CNTs with intermediate AR (around 250) was effective in improving the thermal conductivity of cement paste, increasing it by 15% with relatively low content (0.05%) while did not significantly impair the fresh and mechanical performance of the composite.

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Section: Testing Methodsmentioning

confidence: 99%

“…In turn, the squeeze flow test has been shown to be a precise tool to evaluate the rheological properties of cement-based composites [37], [41] and is more sensitive to small property variations.…”

Section: Rheological Behaviormentioning

confidence: 99%

Effect of Carbon Nanotubes (CNTs) aspect ratio on the rheology, thermal conductivity and mechanical performance of Portland cement paste

Batiston

Gleize

Mezzomo

et al. 2021

Rev. IBRACON Estrut. Mater.

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“…The mixing procedure used consists of two steps, starting with the dry mortar in the bowl and mixer at speed I (rotation of the mixing paddle at 140 rpm and planetary movement at 62 rpm): (1) continuous addition of half of the water content in a constant rate (≈5 g/s, during approximately 40 s) followed by mixing until 60 s; (2) repetition of step 1, with the rest of the water (total mixing time: 120 s). This two‐step mixing procedure produces well mixed mortars and minimizes variations on the rheological results 4,13,14 . Apparent density and air content were determined by gravimetric method (Brazilian standard ABNT NBR 13278/2005) immediately after mixing.…”

Section: Methodsmentioning

confidence: 99%

“…This two-step mixing procedure produces well mixed mortars and minimizes variations on the rheological results. 4,13,14 Apparent density and air content were determined by gravimetric method (Brazilian standard ABNT NBR 13278/2005) immediately after mixing.…”

Section: Mixing Proceduresmentioning

confidence: 99%

Pressure mapped squeeze flow (PMSF): Extending rheological characterization of mortars beyond traditional rheometry

Grandes

Rego

Rebmann

et al. 2023

Int J Ceramic Engine & Sci

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The rheometric techniques available for the evaluation of mortars involve a different set of flow conditions. Squeeze flow is based on the compression of the sample with gap reduction and geometric restrictions, providing important information even when phase separation occurs and an evaluation in conditions similar to those found in several practical situations for many classes of materials, including cement‐based and ceramics. Traditional squeeze flow results are related to bulk normal force and height variation of a sample compressed between parallel plates. Additional information regarding boundary conditions at the interfaces or phenomena related to differential flow can be obtained through further instrumentation of the test. The combination of squeeze flow and a pressure mapping technique has been recently proposed, with great potential for the analysis of cement‐based materials and other granular suspensions. In this work, four mortars were evaluated by the pressure mapped squeeze flow (PMSF) method in two different displacement rates, and new ways to analyze the results were developed to expand the understanding of the flow through the technique, including plotting the pressure along multiple circumferences and an analysis of variation in each radial position. PMSF results were also compared to rotational rheometry and flow table tests for the first time, and concepts of interparticle separation were employed to discuss microstructural aspects of the flow. Due to the variety of mix designs (admixtures, particle size distribution, air content, water content, and other factors), the mortars presented diverse behaviors, ranging from primarily viscous or plastic flows to more granular responses (related to friction between particles with localized formation of jammed structures due to liquid phase migration). This work is part of an effort to establish a foundation for PMSF as a rheometric method that can be used for the analysis of a wide range of materials.

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“…As the aim of this work was to develop a mortar with ornamental rock waste to be applied in a mechanized projected way and within the parameters of the Brazilian standard, it was tested in the fresh and hardened state. With the amount of water and superplasticizer known, the mortars were molded following the NBR 13276 [28] procedures and tested by the fresh state for squeeze flow [29], mass density in the fresh state and the incorporated air content [30] as well as water retention [31]. Like the consistency index, the squeeze flow test is used to determine workability.…”

Section: Molding Of Specimens -Tests In Hardened Statementioning

confidence: 99%

Feasibility Analysis of Mortar Development with Ornamental Rock Waste for Coating Application by Mechanized Projection

Paes¹,

Alexandre²,

Xavier³

et al. 2022

Sustainability

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The industrial production of lime generates greenhouse gases, which contributes to increase the global warming. Therefore, the present study evaluated the feasibility of replacing lime by ornamental rock waste (ORW) as a by-product of the related stone industry, and developed a cost-effective mortars. These new low-costing mortars are intended as fresh fluid paste coatings to be applied on walls by the mechanized projection technique. The ornamental rock waste was collected from a marble and granite industry as ground stone. It was finely crushed before mixing with cement, sand, water and superplasticizer in amounts of 1.0% (R01), 1.2% (R02) and 1.3% (R03), to prepare the mortars, which had the mixture, cement: ORW: sand, 1:1:4 in wt.%. These novel mortars were characterized in both fresh, for well projection, and hardened state, to evaluate the properties after curing performance. The results showed that mortar R03, achieved the best results and did not present cracks in the hardened state. Its water retention was found above 30%. Both tensile strength of 0.312 MPa and compressive strength 7.88 MPa, which are above the corresponding minimum required by the standard for external coating. Water absorption by immersion of 19.37% and void content of 20.23% were close to the corresponding values for hydrated lime mortar. Dry shrinkage showed that the new R03 mortar reached more than 90% of their total retraction at 7 days of cure without sign of cracking. These findings revealed the R03/ornamental rock waste -based mortar applied by mechanized projection as a promising sustainable substitute for common lime-based mortar.

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Experimental Developments of the Squeeze Flow Test for Mortars

Cited by 5 publications

References 4 publications

Effect of Carbon Nanotubes (CNTs) aspect ratio on the rheology, thermal conductivity and mechanical performance of Portland cement paste

Effect of Carbon Nanotubes (CNTs) aspect ratio on the rheology, thermal conductivity and mechanical performance of Portland cement paste

Pressure mapped squeeze flow (PMSF): Extending rheological characterization of mortars beyond traditional rheometry

Feasibility Analysis of Mortar Development with Ornamental Rock Waste for Coating Application by Mechanized Projection

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