Behaviour of a high-performance self-compacting concrete (HPSCC) with ternary mixtures of nano- and microsilica in the presence of chlorides

2020 ◽  
Vol 70 (339) ◽  
pp. 221
Author(s):  
E. Reyes ◽  
J. Massana ◽  
F. Alonso ◽  
N. León ◽  
A. Moragues
Keyword(s):  
High Performance ◽  
Total Content ◽  
Chloride Penetration ◽  
Ternary Mixtures ◽  
Chloride Diffusion ◽  
High Resistivity ◽  
Self Compacting Concrete ◽  
High Durability ◽  
Chloride Resistance ◽  
Binary And Ternary Mixtures

In this paper, the influence of additions of nanosilica (nSi) and microsilica (mSi) on the behav­iour of binary and ternary mixtures in chloride environments is studied. The main objective is to obtain high-performance self-compacting concrete (HPSCC) with a high durability which can meet specific demands in such aggressive environments. Ten blends were manufactured using Portland cement (CEM I 52.5 R) and additions of nSi and mSi in binary and ternary mixtures. The results of three tests frequently used to evaluate resistance to chloride penetration– electrical resistivity, migration and chloride diffusion –were studied and compared. Both binary and ternary mixtures presented significant improvements in chloride resistance, generally in proportion to the total content of the addition. In all the ternary mixtures, high resistivity is obtained, which indicates that such mixtures have a notably low chloride penetrability. Furthermore, these mixtures provided extremely low chloride diffusion coefficients even at small addition ratios.

Energy saving technology for sintering of black bricks from high-siliceous clay

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3123-3131
Author(s):  
Mario Flores Nicolas ◽  
Marina Vlasova ◽  
Pedro Antonio Márquez Aguilar ◽  
Mykola Kakazey ◽  
Marcos Mauricio Chávez Cano ◽  
...  
Keyword(s):  
Low Temperature ◽  
Oxygen Deficiency ◽  
Glass Ceramics ◽  
Total Content ◽  
Ceramic Materials ◽  
Ternary Mixtures ◽  
High Porosity ◽  
Reducing Conditions ◽  
Binary And Ternary Mixtures ◽  
Dark Color

AbstractThe low-temperature synthesis of bricks prepared from high-siliceous clays by the method of plastic molding of blanks was used. For the preparation of brick blanks, binary and ternary mixtures of high-siliceous clays, black sand, and bottle glass cullet were used. Gray-black low-porosity and high-porosity ceramics was obtained by sintering under conditions of oxygen deficiency. It has been established that to initiate plastic in mixtures containing high-siliceous clay, it is necessary to add montmorillonite/bentonite additives, carry out low-temperature sintering, and introduce low-melting glass additives with a melting point ranging from 750 to 800 °C. The performed investigations have shown that the sintering of mixtures with a total content of iron oxide of about 5 wt% under reducing conditions at Tsint. = 800°C for 8 h leads to the formation of glass ceramics consisting of quartz, feldspars, and a phase. The main sources of the appearance of a dark color is the formation of [Fe3+O4]4- and [Fe3+O6]9- anions in the composition of the glass phase and feldspars. By changing the contents of clay, sand, and glass in sintering, it is possible to obtain two types of ceramic materials: (a) in the form of building bricks and (b) in the form of porous fillers.

Experimental Research on Chloride Resistance of Concrete with Isobutyl-triethoxy-silane

2015 ◽  
Vol 744-746 ◽  
pp. 1416-1421
Author(s):  
Qi Wang ◽  
Hai Yang Luan ◽  
Ying Fang Fan
Keyword(s):  
Experimental Research ◽  
Diffusion Coefficients ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Chloride Resistance ◽  
Chloride Migration ◽  
Concrete Materials

The effect of different layers of silane impregnation on chloride resistance of concrete materials at various curing ages is systematically discussed. The chloride resistance of two types of concrete specimens with surface silane impregnation has been investigated through the Rapid Chloride Migration (RCM) method. The testing results indicate that the chloride penetration can be effectively restrained by silane impregnation, and the chloride diffusion coefficients of samples are significantly decreased. After curing for 28 days, when compared to the untreated samples, the chloride diffusion coefficients of two types of concrete specimens both with two layers of silane impregnation decreased by 37.4%, 37.6% respectively.

Comparison of chloride penetration into surface-treated concrete in artificial and natural environments

2016 ◽  
Vol 20 (9) ◽  
pp. 1315-1324 ◽  
Author(s):  
Jianfeng Dong ◽  
Yuxi Zhao ◽  
Yueliang Gan ◽  
Chaomei Ding ◽  
Qiming He
Keyword(s):  
Diffusion Coefficients ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Natural Environments ◽  
Nacl Solution ◽  
Normal Concrete ◽  
Wetting And Drying

This study investigated the penetration of chloride into surface-treated high-performance concrete and normal concrete in natural and accelerated environments. Both high-performance concrete and normal concrete were applied in a real port. Concrete specimens that were cast together with the concrete port were transported to the laboratory and subjected to wetting and drying cycles with NaCl solution. The chloride contents of the specimens in the laboratory and the in situ components were tested. The chloride diffusion coefficients and surface chloride contents were calculated based on Fick’s second law. The results show that high-performance concrete and surface treatment clearly slow the chloride penetration into the concrete both in the laboratory and in situ. The chloride contents on the surface and in the concrete in the components of the concrete port are higher during the summer than during the winter. The chloride penetration performance in the concrete of real structures cannot be inferred from its performance in specimens under artificial environments in the laboratory.

Water Transport Properties and Depth of Chloride Penetration in Ultra High Performance Concrete

2016 ◽  
Vol 711 ◽  
pp. 137-142 ◽  
Author(s):  
Daniel Dobias ◽  
Radka Pernicova ◽  
Tomas Mandlik
Keyword(s):  
Water Transport ◽  
High Performance ◽  
Moisture Absorption ◽  
High Performance Concrete ◽  
Chloride Transport ◽  
Chloride Ions ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Ultra High Performance Concrete ◽  
Depth Of Penetration

Properties of water transport and depth of chloride penetration into the Ultra High Performance Concrete (hereafter as UHPC) with mild steel fibres are presented in this paper. The main aim of this experimental part of work is to obtain sufficiently accurate input data for the evaluation of long-term durability of architectural concrete which are connected with water transport and its accompanying effects such as biological degradation or chloride transport. The article also presents the one dimensional chloride diffusion into UHPC which can be potentially dangerous particularly for durability of reinforced concrete structures. For the simulation of aggressive environments the concrete samples were exposed to chloride solution for one year. Measured data were examined in relation to the depth of penetration of chloride ions into the UHPC structure. Comparative measurements with normal strength concrete (hereafter as NSC) are done as well. An about five-time lower value of moisture absorption of UHPC compared to the NSC was observed and further the curve of chloride penetration into the structure is significantly steeper for UHPC samples.

Transport properties of high-performance cementitious composites incorporating micro and nano SiO2 into the binder

2012 ◽  
Vol 19 (4) ◽  
pp. 415-421 ◽  
Author(s):  
Mostafa Jalal
Keyword(s):  
Water Absorption ◽  
Transport Properties ◽  
High Performance ◽  
Chloride Penetration ◽  
Binder Content ◽  
Cementitious Composites ◽  
Capillary Absorption ◽  
Nano Silica ◽  
Self Compacting Concrete ◽  
Concrete Properties

AbstractIn this paper, transport properties of high-performance self-compacting concrete (SCC), as one of the important cementitious composites incorporating micro and nano silica (NS) (SiO2) into the binder, have been investigated. For this purpose, different mixtures were designed with different amounts of silica fume (SF) and NS admixtures. Different binder contents were also investigated to observe the binder content effect on the concrete properties. Corrosion behavior was evaluated by chloride penetration and resistivity tests. Water absorption and capillary absorption were also measured as other durability related properties. The results showed that water absorption, capillary absorption, and Cl ion percentage decreased rather significantly in the mixtures containing admixtures especially the blend of SF and NS. By addition of the admixtures, resistivity of the SCC mixtures increased, which can lead to reduction of corrosion probability.

Inner Damage and Anti-Chloride Penetration of High-Performance Concrete under Axial Tensile Load

2011 ◽  
Vol 261-263 ◽  
pp. 1210-1214
Author(s):  
Fu Xiang Jiang ◽  
Lei Xin ◽  
Tie Jun Zhao ◽  
Xiao Mei Wan
Keyword(s):  
Diffusion Coefficient ◽  
High Performance ◽  
High Performance Concrete ◽  
Tensile Load ◽  
Total Porosity ◽  
Tensile Loading ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Uniaxial Tensile ◽  
Chloride Diffusion Coefficient

The total porosity of high performance concrete specimens after different level uniaxial tensile loading were measured to reflect the damage degree of mechanical load to the microstructure of the concrete. Meanwhile, considering the environmental characteristics of the ocean tidal zone, chloride penetration tests of the concrete were carried out with salt solution capillary absorption method. Based on the profile of chloride measured from specimens, chloride diffusion coefficients of the concrete under uniaxial tensile load with different levels are determined further by Fick’s second law. Results show that both of total porosity and chloride diffusion coefficient of the concrete are increased significantly after short-term tensile loading. And the evolutions of the porosity and chloride diffusion coefficient are similar with the development of micro-cracks under uniaxial tensile load.

Influence of Polypropylene Fiber and Silica Fume on the Chloride Penetration of High Performance Concrete with Fly Ash

2009 ◽  
Vol 405-406 ◽  
pp. 329-339
Author(s):  
Jing Liu ◽  
De Hua Deng ◽  
Ming Yin ◽  
Xu Li Hu
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
Chloride Penetration ◽  
Interfacial Zone ◽  
Fly Ash Concrete ◽  
Chloride Resistance ◽  
The Matrix

In this paper, the influence of polypropylene fibers (PPF) and silica fume (SF) on chloride penetration of high performance concrete (HPC) containing fly ash (FA) was examined. Three different HPC in which the amount of ordinary Portland cement is 360 kg/m3, via., A concrete with 120 kg/m3 of FA, B concrete with 0.9 kg/m3 of PPF and 120 kg/m3 of FA, C concrete with 0.9 kg/m3 of PPF and 96 kg/m3 of FA and 24 kg/m3 of SF were used for the study. Chloride resistance of concrete was evaluated. From the tests, it is found that the incorporation of PPF and no SF has less influence on the chloride resistance of the fly ash concrete at the age of 28 days. SEM examines B and C concretes specimens illustrating that just incorporating PPF induced more porous fiber-matrix interfacial zone (FMIZ) in B concrete which is detrimental to the chloride resistance, but the microstructures of both the matrix and FMIZ in C concrete with PPF and SF are denser. The plastic shrinkage cracking test proves that the cracking areas on the surface of B and C concrete with PPF are 12.2% and 20.7% of A concrete without PPF respectively.

scholarly journals Effects of Autogenous and Stimulated Self-Healing on Durability and Mechanical Performance of UHPFRC: Validation of Tailored Test Method through Multi-Performance Healing-Induced Recovery Indices

2021 ◽  
Vol 13 (20) ◽  
pp. 11386
Author(s):  
Estefanía Cuenca ◽  
Francesco Lo Monte ◽  
Marina Moro ◽  
Andrea Schiona ◽  
Liberato Ferrara
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Concrete Structures ◽  
Chloride Penetration ◽  
Fiber Reinforced Concrete ◽  
Test Method ◽  
Experimental Methodology ◽  
Chloride Diffusion ◽  
Self Healing ◽  
Crack Sealing

Chloride diffusion and penetration, and consequently chloride-induced corrosion of reinforcement, are among the most common mechanisms of deterioration of concrete structures, and, as such, the most widely and deeply investigated as well. The benefits of using Ultra-High Performance (Fiber-Reinforced) Concrete—UHP(FR)C to extend the service life of concrete structures in “chloride attack” scenarios have been addressed, mainly focusing on higher “intrinsic” durability of the aforementioned category of materials due to their compact microstructure. Scant, if nil, information exists on the chloride diffusion and penetration resistance of UHPC in the cracked state, which would be of the utmost importance, also considering the peculiar (tensile) behavior of the material and its high inborn autogenous healing capacity. On the other hand, studies aimed at quantifying the delay in chloride penetration promoted by self-healing, both autogenous and autonomous, of cracked (ordinary) concrete have started being promoted, further highlighting the need to investigate the multidirectional features of the phenomenon, in the direction both parallel and orthogonal to cracks. In this paper, a tailored experimental methodology is presented and validated to measure, with reference to its multidirectional features, the chloride penetration in cracked UHPC and the effects on it of self-healing, both autogenous and stimulated via crystalline admixtures. The methodology is based on micro-core drilling in different positions and at different depths of UHPC disks cracked in splitting and submitted to different exposure/healing times in a 33g/L NaCl aqueous solution. Its validation is completed through comparison with visual image analysis of crack sealing on the same specimens as well as with the assessment of crack sealing and of mechanical and permeability healing-induced recovery performed, as previously validated by the authors, on companion specimens.

Electrical conductivity of systems based on Na3AlF6-SiO2 melt

2013 ◽  
Vol 67 (10) ◽  
Author(s):  
Michal Korenko ◽  
Jozef Priščák ◽  
František Šimko
Keyword(s):  
Electrical Conductivity ◽  
Boron Nitride ◽  
Concentration Dependence ◽  
High Performance ◽  
Impedance Measurement ◽  
Electrolyte Composition ◽  
Ternary Mixtures ◽  
Concentration Region ◽  
Binary And Ternary Mixtures ◽  
Tube Cell

AbstractThe electrical conductivity of molten binary and ternary mixtures based on the NaF-AlF3-SiO2 system was investigated by means of a tube-cell (composed of pyrolytic boron nitride) with stationary electrodes. An impedance/gain-phase analyser (National Instruments; a high-performance modular chassis controlled by Labview™ software) was used for the cell impedance measurement. The conductivity was found to vary linearly with temperature in all the mixtures investigated. The concentration dependence of electrical conductivity (isotherms) thus obtained was divided into two parts. The first represents the concentration region of up to 10 mole % of SiO2, the second the region with a higher concentration of SiO2 (from 10 mole % to 40 mole %). While the conductivity decreased considerably with the concentration of SiO2 in the second part, it increased surprisingly in the low concentration range. From these results, the influence of electrolyte composition and temperature on the electrical conductivity was examined.

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