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.

Effects of fly ash and cement content on rheological, mechanical, and transport properties of high-performance self-compacting concrete

2012 ◽  
Vol 19 (4) ◽  
pp. 393-405 ◽  
Author(s):  
Mostafa Jalal ◽  
Esmaeel Mansouri
Keyword(s):  
Fly Ash ◽  
Transport Properties ◽  
Rheological Properties ◽  
High Performance ◽  
Cement Content ◽  
Chloride Ion ◽  
Flow Time ◽  
Capillary Absorption ◽  
Self Compacting Concrete ◽  
Funnel Flow

AbstractRheological, mechanical, and transport properties of high-performance self-compacting concrete (HPSCC) mixes with different cement contents and fly ash percentages are studied in this research. Different HPSCC mixtures were investigated with cement contents of 400, 450, and 500 kg/m3 and fly ash percentages of 5%, 10%, and 15%. In order to achieve an enhanced durability, the aggregate grading curve was modified and improved based on power 0.45 grading curve. For a better understanding of fly ash effect and comparison purposes, a constant water to binder ratio (w/b=0.38) was used. The rheological properties were observed through slump flow time and diameter and V-funnel flow time. Mechanical properties including compressive and splitting tensile strength were determined at 7, 28, and 90 days. A comprehensive transport investigation was carried out using water absorption, capillary absorption, chloride ion percentage, and resistivity tests. The results showed a desirable improvement in rheological properties, and the compressive strength improved by about 10% for 15% fly ash at 90 days. A relatively significant improvement was also considered in all transport properties by increasing the fly ash percentage and cement content, especially at higher ages.

scholarly journals The Impact of the Amount and Length of Fibrillated Polypropylene Fibres on the Properties of HPC Exposed to High Temperature / Wpływ Ilosci I Długosci Fibrylowanych Włókien Polipropylenowych Na Własciwosci Hpc Poddanego Działaniu Wysokiej Temperatury

2010 ◽  
Vol 56 (1) ◽  
pp. 57-68 ◽  
Author(s):  
I. Hager ◽  
T. Tracz
Keyword(s):  
High Temperature ◽  
Surface Water ◽  
Water Absorption ◽  
Transport Properties ◽  
High Performance ◽  
Gas Permeability ◽  
Research Programme ◽  
Polypropylene Fibres ◽  
Residual Transport ◽  
The Impact

Abstract This paper presents the results of research on high performance concretes (HPC) modified by the addition of polypropylene fibres (PP fibres). The scope of the research was the measurement of the residual transport properties of heated and recooled concretes: gas permeability and surface water absorption. Seven types of concrete modified with fibrillated PP fibres were tested. Three lengths: 6, 12 and 19 mm and three amounts of fibres: 0, 0.9 and 1.8 kg/m3 were used. The research programme was designed to determine which length of fibres, used in which minimum amount, will, after the fibres melt, permit the development of a connected network and pathway for gases and liquids.

scholarly journals Transport Properties and Resistance Improvement of Ultra-High Performance Concrete (UHPC) after Exposure to Elevated Temperatures

Buildings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 416
Author(s):  
Yunfeng Qian ◽  
Dingyi Yang ◽  
Yanghao Xia ◽  
Han Gao ◽  
Zhiming Ma
Keyword(s):  
Compressive Strength ◽  
Transport Properties ◽  
High Temperatures ◽  
High Performance ◽  
High Performance Concrete ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Capillary Absorption ◽  
Self Healing

Ultra-high performance concrete (UHPC) has a high self-healing capacity and is prone to bursting after exposure to high temperatures due to its characteristics. This work evaluates the damage and improvement of UHPC with coarse aggregates through mechanical properties (compressive strength and ultrasonic pulse velocity), transport properties (water absorption and a chloride diffusion test), and micro-properties such as X-ray diffraction (XRD), Mercury intrusion porosimetry (MIP), and Scanning electronic microscopy (SEM). The result demonstrates that polypropylene (PP) fibers are more suitable for high temperature tests than polyacrylonitrile (PAN) fibers. The result shows that 400 °C is the critical temperature point. With the increase in temperature, the hydration becomes significant, and the internal material phase changes accordingly. Although the total pore volume increased, the percentage of various types of pores was optimized within 400 °C. The mass loss gradually increased and the ultrasonic pulse velocity gradually decreased. While the compressive strength first increased and then decreased, and the increase occurred within 25–400 °C. As for the transport properties, the chloride migration coefficient and capillary absorption coefficient both increased dramatically due to the higher sensitivity to temperature changes. The results of the property improvement test showed that at temperatures above 800 °C, the compressive strength recovered by more than 65% and the ultrasonic pulse velocity recovered by more than 75%. In terms of transport properties, compared to the results before self-healing, the chloride migration coefficient decreased by up to 59%, compared with 89% for the capillary absorption coefficient, after self-healing at 800 °C. With respect to the enhancement effect after exposure to high temperatures, the environment of a 5% Na2SO4 solution was not as good as the clean water environment. The corresponding changes in microstructure during the high temperatures and the self-healing process can explain the change in the pattern of macroscopic properties more precisely.

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.

scholarly journals Application of Response Surface Methodology for Chloride Transport Properties in Nano Metaclayed-UHPC

CONSTRUCTION ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 31-39
Author(s):  
Mohd Faizal Md Jaafar ◽  
Muhd Norhasri Muhd Sidek ◽  
Hamidah Mohd Saman ◽  
Khairunisa Muthusamy ◽  
Norhaiza Ghazali ◽  
...  
Keyword(s):  
Transport Properties ◽  
Response Surface ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Transport ◽  
Chloride Content ◽  
Penetration Resistance ◽  
Chloride Penetration ◽  
Reinforced Concrete Structure ◽  
Chloride Penetration Resistance

The major concern on the deterioration of reinforced concrete structure is due to the corrosion of steel reinforcement from the aggressive environment such as chloride penetration. Ultra-high performance concrete (UHPC) is an advanced concrete material having ultra-high strength with excellent durability properties. Inclusion of nano metaclay in UHPC is expected to overcome the chloride transport properties in UHPC by providing nano filler effect. Two (2) assessments were conducted which are chloride content and chloride depth were examined. All the concrete specimens were immersed in 3% NaCl solution up to 365 days and the tests conducted were performed at 3, 7, 28, 56, 91, 182 and 365 days. Response surface method (RSM) was performed to evaluate the interaction and relationship between operating variables (compressive strength and nano metaclay content). Based on RSM analysis, inclusion of nano metaclay in UHPC have good relationship towards the chloride resistance characteristics and adequate durability performance in terms of chloride penetration resistance. The results exhibited that inclusion of 1% nano metaclay significantly and positively affect in term of chloride penetration resistance.

scholarly journals Neutron Radiography Study of Laboratory Ageing and Treatment Applications with Stone Consolidants

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 635 ◽  
Author(s):  
Matea Ban ◽  
Tim De Kock ◽  
Frédéric Ott ◽  
Germana Barone ◽  
Andreas Rohatsch ◽  
...  
Keyword(s):  
Water Absorption ◽  
Neutron Radiography ◽  
Reactive Systems ◽  
Ultrasonic Pulse Velocity ◽  
Pulse Velocity ◽  
Tetraethyl Orthosilicate ◽  
Capillary Absorption ◽  
Artificial Ageing ◽  
Nano Silica ◽  
Stone Consolidants

A nano-silica consolidant and nano-titania modified tetraethyl-orthosilicate were applied on two building stones, a carbonate and a silicate, by brush, poultice or capillary absorption. Neutron radiography was used to monitor capillary water absorption, and to analyse changes in physical properties caused by heat treatment of specimens for the purposes of artificially ageing and different treatment applications with stone consolidants. Moreover, ultrasonic pulse velocity and gravimetrically determined water absorption were analysed to cross-validate neutron radiography. The results reveal that reactive systems like tetraethyl-orthosilicates need an unknown period for polymerisation, which makes nano-silica consolidants more favourable for construction follow-up work. While polymerisation is incomplete, hydrophobic behaviour, water trapping and pore clogging are evident. Within the tetraethyl-orthosilicate treatment, poultice and brushing are strongly influenced by the applicant, which results in wide ranging amounts of water absorbed and anomalous water distributions and kinetics. The carbonate lithotype displays polymerisation initiated in the core of the specimen, while the lateral surfaces are still mostly hydrophobic. Reaction time differences can be attributed to the different amounts of consolidants applied, which is a result of the chosen application settings. Artificial ageing of stone specimens is a prerequisite when mechanical strength gain is studied, as demonstrated by sound speed propagation.

scholarly journals The transport properties of cement mortars subjected to freeze-thaw cycles

2018 ◽  
Vol 49 ◽  
pp. 00128
Author(s):  
Alicja Wieczorek ◽  
Marcin Koniorczyk ◽  
Dalia Bednarska ◽  
Kalina Grabowska
Keyword(s):  
Absorption Coefficient ◽  
Water Absorption ◽  
Transport Properties ◽  
Positive Impact ◽  
Gas Permeability ◽  
Cement Matrix ◽  
Capillary Absorption ◽  
Water Absorption Coefficient ◽  
Freeze Thaw ◽  
Cement Mortars

The parameters characterizing the microstructure of cementbased materials, such as porosity or permeability, determine not only durability, but also risk of degradation of the cement matrix due to an aggressive environment. The report presents results of a research on transport properties of cement mortars subjected to cyclic water freezing. Mortars prepared on the basis of two different cements were the object of the research: Portland cement CEM I 42.5R and Portland blast-furnace slag cement CEM III/A 42.5N LH/HSR/NA, with two water-cement ratio (w/c=0.45 and 0.40). The experimental study was carried out in order to determine the relationship between intrinsic permeability and the water absorption coefficient in relation to the number of freeze-thaw cycles. The evolution of transport coefficients was determined using a capillary absorption test and the modified RILEM-Cembureau method. It was established that the degradation processes induced an increase of transport properties. Moreover, the microcracks had a more significant influence on permeability and lesser influence on the water absorption coefficient. The gas permeability of damaged mortar changed very significantly, an increase with several orders of magnitude could be noticed. Moreover, the positive impact of CEM III on ice-induced degradation was also visible.

Variation of Diffusion Coefficient for Selected Binary and Ternary Concrete Mixtures Considering Concrete Aging Effect

2018 ◽  
Vol 761 ◽  
pp. 144-147 ◽  
Author(s):  
Petr Konečný ◽  
Petr Lehner ◽  
Pratanu Ghosh ◽  
Quang Tran
Keyword(s):  
Diffusion Coefficient ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Ion ◽  
Aging Effect ◽  
Chloride Penetration ◽  
Concrete Mixtures ◽  
Concrete Properties ◽  
Chloride Ion Penetration ◽  
Non Destructive

The paper deals with the variation of resistance of selected High Performance Concrete (HPC) materials against chloride ion penetration. The resistance of chloride penetration is described by means of the diffusion coefficient and it is derived from emerging non-destructive tests. It is computed from the measurements of surface electrical resistivity (see e.g. AASTHTO TP-95 specification) data. The effect of concrete aging on the diffusion coefficient is taken into account as the concrete properties are time dependent and it is significantly important for High Performance Concrete (HPC) materials.

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