A study of packing parameters that influence the fresh properties of self-compacting concrete

Melo, Cássia Vanessa Albuquerque de; Gomes, Paulo César Correia; Moraes, K. A. M.

doi:10.1590/0366-69132019653752667

Cited by 7 publications

(6 citation statements)

References 14 publications

(41 reference statements)

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“…As for concretes with intermediate packaging (IQ25 and IQ35), the lack of medium sand can be noticed when observing a greater dispersion in the diameters between 0.3 and 2.4 mm (Figure 14). [33,34] present similar analysis and added particles to improve the fit of the curve. In this work, it was decided to work with different levels of packing and to assess whether this difference implies significant impacts on the compressive strength of the concretes.…”

Section: Concretementioning

confidence: 99%

“…The bi varied from 2.55 kg.m -3 /MPa [17] to 15.2 kg.m -3 /MPa [8]. The studies highlighted in Figure 1, [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35], presented the lowest bi values among all mixtures. These works used different distribution modulus for the fine and coarse materials, and higher energy mixers, which improves the dispersion of the particles.…”

Section: Aggregate Packing Optimizationmentioning

confidence: 99%

“…In this work, the aggregates PSD curves showed complementary distributions, which favored the aggregates compaction. [32][33][34] focused on the study of particle packing in concretes, in which the optimization of the granular skeleton was carried out in an inverse way to that presented in this work: adjustments of the aggregate percentages were made first, and then the corresponding "q" value was determined. Even so, several "q" values were used in their studies: 0.29 in [34] study; 0.126 -0.253, with 9 values in total in [32] study; and 0.16, 0.23 and 0.27 in [33] work.…”

Section: General Analysismentioning

confidence: 99%

“…In [33], 0.16, 0.23 and 0.27 were the optimum values to produce concrete mixtures with compressive strengths of 80 MPa, 40 MPa and 25 MPa, respectively. In [34], 0.29 was the optimum value to produce their high-performance concrete mixture. These values of q are not far from those observed in the present study, that showed lower void index for q value around 0.3.…”

Section: General Analysismentioning

confidence: 99%

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Use of numerical method for optimization of granulometric curves in eco-efficient concrete

et al. 2021

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Concrete is the most used construction material and thus, being the cement a significant part of this material, it is also widely used around the world. Cement production is responsible for more than 5% of global CO 2 emissions, which has been continuously increasing. A solution to reduce the cement content in concretes without loss of performance is thorough the particle packing optimization. This work uses practical numerical simulations through linear programming and the modified Andreasen & Andersen model to reduce the void content of aggregate mixtures and produce concretes with superior and intermediate packing levels. A broad range of distribution modulus "q" values were tested. Deviations between the particle size distribution (PSD) curves were calculated in each step of the process. In this study, mixtures with the smallest deviations experimental PSD curves closer to the mathematical packing modeldid not present the lowest void contents. The distribution modulus "q" directly affects the fine aggregate content in the mixtures: lower q values favors higher fine aggregate contents. For concrete granular skeletons composed by sand and gravel, there is a q value below which sand is the top deviation contributor and above which gravel is the top deviation contributor. Moreover, there is a limit to the distribution modulus after which the void content of aggregate skeletons tends to increase. In this study, that was 0.30. Concretes with superior packing (S concrete) and with the lowest distribution factor (q = 0.25) showed better performance in relation to the other studied concretes, with a higher compressive strength at 91 days and with a binder intensity around 6 at 28 days and below 5 at 91 days.

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Section: Concretementioning

confidence: 99%

Section: Aggregate Packing Optimizationmentioning

confidence: 99%

Section: General Analysismentioning

confidence: 99%

Section: General Analysismentioning

confidence: 99%

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Use of numerical method for optimization of granulometric curves in eco-efficient concrete

et al. 2021

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“…A significant number of studies about SCC deal with materials, proportions of the mixtures and their properties in the fresh and hardened state [3][4][5][6][7], with little information about structural properties, such as shear strength, becoming an obstacle to the acceptance of self-consolidating concrete as a high quality structural material [8][9][10][11][12]. The main uncertainty regarding the structural behavior of SCC lies in its shear strength.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of direct shear strength of self-consolidating and conventional concretes

et al. 2021

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The self-consolidating concrete presents properties that improve the constructive process, it has the main characteristic of flowing under its own weight and completely filling the formwork, without the need of compaction. However, the uncertainty about its shear strength, due to the differences in coarse aggregate volume and size of this concrete compared to conventional vibrated concrete, is one of the main barriers to its acceptance. Self-consolidating concrete mixtures requires generally the reduction of coarse aggregate content and addition of fines materials to obtain flowability and the reduction of particles size directly influences the mechanism of aggregate interlock. In this work, two concrete mixtures, conventional and self-consolidating, were used for casting test specimens, submitted to the direct shear test, in order to evaluate the direct shear strength of these concretes. The results showed a reduction of the shear strength for the self-compacting concrete, attributed to the use of coarse aggregate with smaller particle size, the reduced volume of coarse aggregate and the larger fines content in the mixture. The experimental results were compared with equations proposed in the literature, demonstrating that for self-consolidating concrete these equations underestimate the ultimate shear strengths. Thus, this work contributes to the formation of a database aiming the establishment of equations to estimate self-consolidating concrete shear strength.

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Assessment of blended cement containing waste basalt powder: physicomechanical and electrochemical impedance spectroscopy investigations

Abo Hashem,

Gaber,

Ahmed

et al. 2024

Discov Appl Sci

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Basalt powder (BP) is the residue of a plant that crushes basalt stones. This work deals with the effect of waste BP on the properties of cement mortars and the physical properties of hardened mortars. Modified concrete was prepared by partial replacement of BP in amount of 5, 10, 20% by weight of cement. Physico-mechanical properties and corrosion resistance were investigated. Electrochemical impedance spectroscopy (EIS) was used to examine the corrosion behavior of cement pastes with a partial addition of basalt powder in aggressive solutions of 5% NaCl and 5% MgCl2 for up to 270 days. Infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were also performed to investigate the hydration process and microstructure formation of the basalt blended paste. Results indicate that the addition of basalt powder as a partial replacement of cement influences the microstructure of the interfacial transition zone (ITZ), which is denser and stronger than in cement paste without basalt powder. The filler effect of the basalt powder improves the compressive strength of cement paste. Also, comparing BP0 and BP20 in 5% NaCl after 270 days, the partial substitution of cement with BP resulted in a higher compressive strength of 671 and 895 kg/cm2, respectively. The EIS results also showed the highest values of Rp 953 ohms cm2 after 270 days. This high corrosion resistance might indicate the binding by high Al2O3 that reduced the free aggressive chloride ions in the solution.

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A study of packing parameters that influence the fresh properties of self-compacting concrete

Cited by 7 publications

References 14 publications

Use of numerical method for optimization of granulometric curves in eco-efficient concrete

Use of numerical method for optimization of granulometric curves in eco-efficient concrete

Evaluation of direct shear strength of self-consolidating and conventional concretes

Assessment of blended cement containing waste basalt powder: physicomechanical and electrochemical impedance spectroscopy investigations

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