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Performance Of Concrete Made With A Calcined Clay – Limestone-Portland Cement Exposed To Natural Conditions, Fernando Martirena, Ernesto Díaz, Dayran Rocha, Hamed Maraghechi, Karen Louise Scrivener Nov 2019

Performance Of Concrete Made With A Calcined Clay – Limestone-Portland Cement Exposed To Natural Conditions, Fernando Martirena, Ernesto Díaz, Dayran Rocha, Hamed Maraghechi, Karen Louise Scrivener

International Conference on Durability of Concrete Structures

This work presents the results of an investigation carried out to assess durability of concrete made with a calcined clay- limestone-Portland cement with 47% of clinker, hereafter named LC3, produced during an industrial trial in 2013. LC3 was used to cast concrete blocks and later expose them at a natural location at the northern coast of Cuba. Reference concrete was cast with Cuban Portland cement having 88% of clinker. Throughout three years (2015, 2016, 2017) concrete cores were systematically taken and the specimens were subjected to a testing program that included Formation factor, chloride profiling, surface resistivity, air permeability and …


Workability And Freeze-Thawing Performance Of Fiber Reinforced Expansive Self-Consolidating Concrete, Qi Cao, Qq Gao Nov 2019

Workability And Freeze-Thawing Performance Of Fiber Reinforced Expansive Self-Consolidating Concrete, Qi Cao, Qq Gao

International Conference on Durability of Concrete Structures

The aim of this study is to investigate the workability and freeze-thawing performance of fiber reinforced expansive self-consolidating concrete (ESCC). Fibers and expansive agent were used to decrease shrinkage, control cracks and enhance microstructure of the concrete. Steel fibers with three volume fractions (0.25%, 0.50%, 0.75%) of the total volume of concrete and monofilament polypropylene fibers with two volume fractions (0.05%, 0.10%) were used in the test. The freeze-thawing performance was determined by rapid freezing and thawing test. Results indicated that polypropylene fiber shows more sensitivity on slump flow than steel fiber but less impact on T500. The relative dynamic …


Polymer Binder, Impact On The Pull-Out Force Of Macro Fibers In Sprayed Concrete, Klaus Bonin, Christina Neumaier Nov 2019

Polymer Binder, Impact On The Pull-Out Force Of Macro Fibers In Sprayed Concrete, Klaus Bonin, Christina Neumaier

International Conference on Durability of Concrete Structures

Macro-fibers have been used in sprayed concrete for many years now, particularly to prevent cracks from developing in the concrete due to deformation energy. These fibers can be made of steel or plastics and are provided for the Application. The type of fiber to be used is selected based on the building project’s requirements. Usually, the fibers are added to the sprayed concrete in the standard application’s mixture, regardless of whether the concrete is wet or dry (fiber-reinforced concrete or FRC). FRC’s functional principle is to mechanically anchor the steel or polymer fibers in the dense matrix of the binder …


Strength And Durability Performance Of Ultra-High-Performance Cementitious Composite Enhanced With Carbon Nanofibres, Jlg Nim, Sudharshan Naidu Raman, Mfm Zain, R Hamid, Fc Lai Nov 2019

Strength And Durability Performance Of Ultra-High-Performance Cementitious Composite Enhanced With Carbon Nanofibres, Jlg Nim, Sudharshan Naidu Raman, Mfm Zain, R Hamid, Fc Lai

International Conference on Durability of Concrete Structures

Ultra-high-performance concrete (UHPC) is known for exhibiting excellent strength and a more durable matrix compared to conventional concrete. Typically UHPC consists of carefully selected constituent materials of: ultrafine graded sand, silica fume (or other alternative binders), steel micro-fibres, and ordinary (or special blends) Portland cement. This study was initiated to synthesize a new blend of Ultra-high-performance cementitious composite (UHPCC) with compressive strength higher than 150 MPa under normal curing conditions, and to investigate the influence of two different sources of carbon nanofibres (CNF) on its strength, durability and microstructure properties. Several mix designs with different CNF percentages were designed, optimised …


Post-Cracking Behavior Of Cementitious Composite Incorporating Nano-Silica And Basalt Fiber Pellets, Ahmed Bedwiy, Mohamed T. Bassuoni, Ehab El-Salakawy Nov 2019

Post-Cracking Behavior Of Cementitious Composite Incorporating Nano-Silica And Basalt Fiber Pellets, Ahmed Bedwiy, Mohamed T. Bassuoni, Ehab El-Salakawy

International Conference on Durability of Concrete Structures

Recently, fiber reinforced polymers (FRPs) have been increasingly used to reinforce concrete structures in harsh environments, due to their non-corrodible nature. Developing a nonferrous reinforcement system (corrosion-free system) for concrete using FRP bars along with discrete fibers is a promising option for exposed concrete structures in cold regions or marine environments. Incorporating highly efficient non-metallic fibers into any cementitious composite is capable of reducing bleeding, controlling shrinkage cracking, and improving toughness and impact resistance. Therefore, in this study, a new type of basalt fiber pellets with high tensile strength was investigated. This paper reports on the flexural performance of the …


Long Term Permeability And Acid Resistance Of Selfcompacting Concretes With Micro And Nano Mineral Additions, Gonzalo Barluenga, Cynthia Guardia, Javier Puentes, Nelson Flores Nov 2019

Long Term Permeability And Acid Resistance Of Selfcompacting Concretes With Micro And Nano Mineral Additions, Gonzalo Barluenga, Cynthia Guardia, Javier Puentes, Nelson Flores

International Conference on Durability of Concrete Structures

Self-Compacting Concrete (SCC) can incorporate different types of Supplementary cementitious materials (SCM), as filler and other active mineral additions, to increase the amount of paste without increasing the amount of cement. SCM modify the SCC hardened microstructure due to the filler effect, the seeding effect as nucleation points for hydration products and the pozzolanic effect in the case of reactive SCM, as mineral additions (MA). The pore network is also modified which produce changes in the permeability of SCC. It is generally considered that the increase of fine particles improves SCC durability due to the larger compactness of the hardened …


Effect Of Nanosilica On The Sulfate Attack Resistivity Of Cement Mortar, Pengkun Hou, Zh Guo, Q Yu, N Xie, X Cheng, Sp Shah Nov 2019

Effect Of Nanosilica On The Sulfate Attack Resistivity Of Cement Mortar, Pengkun Hou, Zh Guo, Q Yu, N Xie, X Cheng, Sp Shah

International Conference on Durability of Concrete Structures

The effect of nanosilica on the sulfate attack resistivity of cement mortar was investigated through study on the mechanical property evolution and the length change of the cement mortar under 5 wt.% sodium sulfate for 6 months. Meanwhile, the effects were compared with those of fly ash-replacement mortar. Results showed that by taking the advantages of nanosilica and fly ash in improving the property of cement mortar at early and later ages, the sulfate attack resistance of cement mortar can be enhanced in mechanical property increase and expansion reduction. Further, it implies that a combination of both pozzolans could enhance …


The Synergistic Effect Of Nano-Silica With Slag On Frost Resistance Of Concrete, Yuan Lianwang, Zhou Zonghui, P Du, X Cheng, P Hou, L Zhang, Q Li Nov 2019

The Synergistic Effect Of Nano-Silica With Slag On Frost Resistance Of Concrete, Yuan Lianwang, Zhou Zonghui, P Du, X Cheng, P Hou, L Zhang, Q Li

International Conference on Durability of Concrete Structures

The frost resistance of concrete is one of the most important factors for its durability. Supplementary cementitious materials could effectively improve the frost resistance of concrete. On this basis, the synergistic effect of nano-silica (NS) with slag on the frost resistance of concrete is better than the single, which was investigated. Nano-silica and slag were employed as a partial substitute of cement. The effect of these on the related indexes, including the mass loss, relative dynamic elastic modulus and porosity of concrete were measured after specified number of freeze and thaw cycles. Results show that the frost resistance of nano-silica …


Enhancement Of Durability Characteristics Of Geopolymer Concrete With Manufactured Sand, Abdul Aleem, T Shanmuga Priya Nov 2019

Enhancement Of Durability Characteristics Of Geopolymer Concrete With Manufactured Sand, Abdul Aleem, T Shanmuga Priya

International Conference on Durability of Concrete Structures

Geopolymer Concrete is the concrete made without using any quantity of cement. Instead the waste material from the thermal power station called fly ash is used as the binding material. This fly ash reacts with alkaline solution like sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) and forms a gel which binds the fine and coarse aggregates. Similarly another artificial material called manufactured sand (M-Sand) is also used as the fine aggregate against the normal river sand. The durability of Geopolymer Concrete with M-sand was studied by casting cubes of size 100 x 100 x 100 mm. The cube specimens were …


A Preliminary Investigation Into Geopolymer Cement Mortar’S Suitability For Providing Resilient Highway Solutions, Bryan Magee, A Wilkinson, D Woodward, S Tretsiakova-Mcnally, P Lemoine Nov 2019

A Preliminary Investigation Into Geopolymer Cement Mortar’S Suitability For Providing Resilient Highway Solutions, Bryan Magee, A Wilkinson, D Woodward, S Tretsiakova-Mcnally, P Lemoine

International Conference on Durability of Concrete Structures

Despite local and national road authorities striving to provide motorists with a durable and safe infrastructure environment, one in six UK roads are currently classed as being in poor condition. In terms of safety, Department for Transport statistics continue to report high numbers of road fatalities; 1,780 in 2015, representing a 3% increase from the previous year. As such, research focused on developing resilient and cost effective planned/preventative highway maintenance solutions remains highly topical. Reported in this paper is research aimed at developing high performance, low impact solutions for both highway repair and skid resistance enhancement. A metakaolin/alkali silicate-based geopolymer …


Comparison Of Lithomarge And Cement-Based Mortars Performance In Aggressive Aqueous Environments, Jacek Kwasny, Timothy A. Aiken, Marios N. Soutsos, Andrew J. Mcintosh, David J. Cleland Nov 2019

Comparison Of Lithomarge And Cement-Based Mortars Performance In Aggressive Aqueous Environments, Jacek Kwasny, Timothy A. Aiken, Marios N. Soutsos, Andrew J. Mcintosh, David J. Cleland

International Conference on Durability of Concrete Structures

The resistance of room temperature cured geopolymer mortar (GPM) against chemical attacks, i.e. sodium and magnesium sulfate solutions, and sulfuric and hydrochloric acid solutions, was evaluated. GPM was formulated using a lithomarge precursor (low-purity kaolin) to achieve 28-day characteristic compressive strength of 60 MPa. Its performance was compared with an equivalent Portland cement mortar (PCM) having the same paste volume and strength grade. 28-day old bar samples were stored in 0.352 mol/L sulfate solutions for 52 weeks whereas 28-day old cube samples were exposed for 8 weeks to acid solutions with concentration of 0.52 mol/L. GPM showed superior performance against …


Influence Of Sulfide On The Onset Of Chloride-Induced Corrosion Of Steel Reinforcement In Alkali-Activated Slags., Maria Criado, Shishir Mundra, Susan Andrea Bernal, John Lloyd Provis Nov 2019

Influence Of Sulfide On The Onset Of Chloride-Induced Corrosion Of Steel Reinforcement In Alkali-Activated Slags., Maria Criado, Shishir Mundra, Susan Andrea Bernal, John Lloyd Provis

International Conference on Durability of Concrete Structures

In alkali-activated slags (AAS), where ground granulated blast furnace slag is used as the main precursor, the presence of reduced sulfur species yields a highly reducing pore solution environment. This study investigates the influence of sulfide on steel passivation in alkali-activated slag mortars immersed in alkaline (1 M NaOH) and alkaline chloride-rich (1 M NaOH with 5 M NaCl) solutions, and the dependency of chloride-induced pitting on the immersion time and the concentration of sulfide in simulated alkali-activated slag pore solutions (containing 0.80 M OH- and 0 M, 0.01 M and 0.45 M HS- ) by means of electrochemical techniques. …


Impact Of Water Content On The Performance Of Alkali-Activated Slag Concretes, Susan A. Bernal, John L. Provis, Jannie S.J. Van Deventer Nov 2019

Impact Of Water Content On The Performance Of Alkali-Activated Slag Concretes, Susan A. Bernal, John L. Provis, Jannie S.J. Van Deventer

International Conference on Durability of Concrete Structures

In this study, we report the effect of varying the water/binder (w/b) ratio on the performance of sodium silicate activated concretes. Compressive strength development and water transport properties of these concretes were assessed, along with their resistance to carbonation. The results demonstrate that varying the water content within a reasonable range induced negligible changes in the compressive strengths of these concretes, when a constant paste content was used. A direct correlation between the w/b ratio and the amount of permeable voids in the concretes was not identified. The carbonation behaviour of these concretes changes prominently depending on the CO2 concentration …


Internal Curing By Sap In Ultra-High Strength Concrete With Cement-Silica Fume-Fly Ash Binder, Jianhui Liu, Caijun Shi, Xianwei Ma Nov 2019

Internal Curing By Sap In Ultra-High Strength Concrete With Cement-Silica Fume-Fly Ash Binder, Jianhui Liu, Caijun Shi, Xianwei Ma

International Conference on Durability of Concrete Structures

Super-absorbed polymer (SAP) is an effective internal curing materials for reducing autogenous shrinkage and improving cracking resistance of ultra-high-strength concrete (UHSC). This study investigated the compressive strength, shrinkage properties of UHSC with cement–silica fume–fly ash binder. The composition of the binder was designed using seven-batch factorial design method. The relationships between the binder composition and the properties were expressed in contours. Results showed that, silica fume could improve the compressive strength and total shrinkage of UHSC. However fly ash reduced the compressive strength and total shrinkage of UHSC to certain extent. On the other hand, under the internal curing of …


Design Of Ternary Blend High-Volume Fly Ash Concrete Mixes Using Hydrated Lime, Chamila Gunasekara, David Law, Sujeeva Setunge Nov 2019

Design Of Ternary Blend High-Volume Fly Ash Concrete Mixes Using Hydrated Lime, Chamila Gunasekara, David Law, Sujeeva Setunge

International Conference on Durability of Concrete Structures

The increase of carbon emission due to annual growth of Portland cement (PC) production has enforced research into the development of sustainable green concrete using a range of readily available industrial waste materials. The present study is focused on developing two high volume fly ash (HVFA) concretes with cement replacement levels 65% (HVFA‒65) and 80% (HVFA‒80). Initially, the required lime for both HVFA concrete mixes were determined, and then the optimized mix design identified, based on 28-day strength, by varying the fly ash‒lime combination. The optimized mixes achieved a compressive strength of 53MPa and 40MPa, for HVFA‒65 and HVFA‒80 concretes, …


Compressive Strength, Free Expansion And Shrinkage Of Expansive Concrete Containing Fly Ash, Warangkana Saengsoy, Rachot Chatchawan, Somnuk Tangtermsirikul Nov 2019

Compressive Strength, Free Expansion And Shrinkage Of Expansive Concrete Containing Fly Ash, Warangkana Saengsoy, Rachot Chatchawan, Somnuk Tangtermsirikul

International Conference on Durability of Concrete Structures

This study is aimed to investigate effect of fly ash on compressive strength, free expansion and shrinkage of expansive concrete. High CaO and low CaO fly ashes are used in this study. The replacement percentages of total binders by fly ash are 0 and 30% by weight. The replacements of expansive additive are 0, 20 and 30 kg/m3 of concrete. The test results revealed that the use of fly ash especially the high CaO fly ash can enhance expansion of expansive concrete at early age. The use of fly ash also reduces shrinkage at long term of the expansive …


Carbonation In Alternative Cementitious Materials: Implications On Durability And Mechanical Properties, Prasanth Alapati, Kimberly E. Kurtis Dr. Nov 2019

Carbonation In Alternative Cementitious Materials: Implications On Durability And Mechanical Properties, Prasanth Alapati, Kimberly E. Kurtis Dr.

International Conference on Durability of Concrete Structures

Understanding the rate and implications of carbonation on strength and durability in alternative cementitious materials (ACMs) is critical in designing ‘green’ concretes for intended service lives. In this paper, three commercially available ACMs, including one calcium aluminate cement (CAC), one calcium sulfoaluminate belite cement (CSA), and one alkali-activated binder using class C fly ash (AA), were evaluated against one portland cement (OPC). Thermogravimetric analysis (TGA) and x-ray diffraction (XRD) techniques were used to understand the effect of carbonation on ACM paste composition. Water sorption tests on both carbonated and uncarbonated cement mortar showed a significant reduction in porosity of this …


Effects Of Temperature And Curing Duration On The Stability Of Slag Cements In Combined Chloride-Sulphate Environments, Joseph Onah Ukpata, P. A. M. Basheer, Leon Black Nov 2019

Effects Of Temperature And Curing Duration On The Stability Of Slag Cements In Combined Chloride-Sulphate Environments, Joseph Onah Ukpata, P. A. M. Basheer, Leon Black

International Conference on Durability of Concrete Structures

This experimental study investigates the effects of temperature and curing duration on the stability of slag blended cement systems exposed at 20 °C and 38 °C to combined sodium chloride (30 g/L) – sodium sulphate (3 g/L) solutions. Two slags, designated as slag 1 and 2, having CaO/SiO2 ratios of 1.05 and 0.94, were respectively blended with Portland cement CEM I 52.5R at 30 wt.% replacement level. Mortar prisms and cubes with w/b ratio of 0.5 and binder/aggregate ratio of 1:3 were then prepared for length and mass changes. The samples were cured in lime water for either 7 …


Probability Model Of Corrosion-Induced Cracking Time In Chloride-Contaminated Reinforced Concrete, Chunhua Lu, Jinmu Yang, Ronggui Liu Jun 2016

Probability Model Of Corrosion-Induced Cracking Time In Chloride-Contaminated Reinforced Concrete, Chunhua Lu, Jinmu Yang, Ronggui Liu

International Conference on Durability of Concrete Structures

Corrosion-induced concrete cover cracking caused by chloride ion is an important indication of durability limit state for marine reinforced concrete (RC) structures and can ultimately determine the structural service life. In this paper, considering the random nature of factors affecting the corrosion cracking process, a probabilistic model which expands on the deterministic model of cover cracking time is developed by using Monte Carlo simulation technique. The results showed that the time to corrosion cracking can be modelled by the Weibull distribution. Finally, the probabilistic analysis for the cracking time is applied to an in-site RC bridge girder with four different …


Progress Of Carbonation In Chloride Contaminated Concretes, Yaocheng Wang, P. A.M. Basheer, S. Nanukuttan, Y. Bai Jun 2016

Progress Of Carbonation In Chloride Contaminated Concretes, Yaocheng Wang, P. A.M. Basheer, S. Nanukuttan, Y. Bai

International Conference on Durability of Concrete Structures

Concretes used in marine environment are generally under the cyclic effect of CO2 and chloride ions (Cl-). To date, the influence of carbonation on ingress of chloride ions in concretes has been widely studied; in comparison, study on the influence of Cl- on the progress of carbonation is limited. During the study, concretes were exposed to independent and combined mechanisms of carbonation and chloride ingress regimes. Profiles of apparent pH and chloride concentration were used to indicate the progress of carbonation and ingress of Cl- in concretes. From the apparent pH profile, a carbonation front …


Carbon Fiber As Anode Material For Cathodic Prevention In Cementitious Materials, Emma Qingnan Zhang, Luping Tang, Thomas Zack Jun 2016

Carbon Fiber As Anode Material For Cathodic Prevention In Cementitious Materials, Emma Qingnan Zhang, Luping Tang, Thomas Zack

International Conference on Durability of Concrete Structures

Cathodic prevention (CPre) technique is a promising method and has been used for the past two decades to prevent steel from corrosion in concrete structures. However, wide application of this technique has been restricted due to high costs of anode materials. In order to lower the cost and further improve this technique, carbon fiber composite anode has been introduced as an alternative anode material with affordable price and other outstanding properties. This paper presents the study of using carbon fiber mesh as anode material for long-term cathodic prevention system and the effect of accelerated current on macro- and microstructure of …


Investigation Of A Novel 3d Non-Destructive Evaluation For Corrosion Process In Reinforced Concrete, Guohao Fang, Biqin Dong, Ningxu Han, Feng Xing Jun 2016

Investigation Of A Novel 3d Non-Destructive Evaluation For Corrosion Process In Reinforced Concrete, Guohao Fang, Biqin Dong, Ningxu Han, Feng Xing

International Conference on Durability of Concrete Structures

X-ray computed microtomography (X-ray μCT) method is proposed to trace the corrosion features of steel bar in cementitious materials. Three-dimensional corrosion morphology (including morphology of steel corrosion, corrosion products and cracks formation) are characterized and reconstructed. Experimental results demonstrate that X-ray μCT can track time-dependent development of corrosion products and the subsequent initiation and propagation of corrosion-induced cracks. In addition, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) are used to morphologically and chemically analyze the corrosion result. The microscopic analysis result is found to be in a very good agreement with the image analysis measured by X-ray μCT. …


An Experimental Study On Effect Of Steel Corrosion On The Bond–Slip Performance Of Reinforced Concrete, Xiaolin Zhang, Xuebing Liang, Hancheng Huang, Haijun Zhou Jun 2016

An Experimental Study On Effect Of Steel Corrosion On The Bond–Slip Performance Of Reinforced Concrete, Xiaolin Zhang, Xuebing Liang, Hancheng Huang, Haijun Zhou

International Conference on Durability of Concrete Structures

This paper studied the effects of reinforcement corrosion on bond performance between rebar and concrete. Tests were carried out to evaluate the degradation of bond between reinforcing steel and concrete for different corrosion levels of reinforcing steel. A series of 20 specimens of different concrete strength with various reinforcing steel corrosion levels were designed and manufactured. Each specimen was casted as a 200-mm concrete cube, and a steel rebar was centrally embedded with two stirrups around it. The steel rebar were corroded using an electrochemical accelerated corrosion technique. The corrosion crack opening width and length were recorded after the corrosion …


Threshold Chloride Concentration Of Stainless Steels In Simulated Concrete Pore Solution, Hailong Wang, Jiayan Ling, Xiaoyan Sun Jun 2016

Threshold Chloride Concentration Of Stainless Steels In Simulated Concrete Pore Solution, Hailong Wang, Jiayan Ling, Xiaoyan Sun

International Conference on Durability of Concrete Structures

To evaluate whether stainless steel can replace carbon steel as rebar in reinforced concrete structures exposed to aggressive environment, the threshold chloride concentration of carbon steel, austenitic and duplex stainless steels were experimentally studied in this paper. The solutions with pH ranging from 9.5 to 13.6 were used herein to simulate the pore liquids in both alkaline and carbonated concretes. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were carried out in the solutions with chloride concentration ranging from 0 to 5.0M and at a temperature around 25°C. The activation of pitting corrosion was determined when corrosion current increased and …


Corrosion-Induced Concrete Cracking Model Considering Corrosion-Filled Paste, Jianfeng Dong, Yuxi Zhao, Yingyao Wu, Weiliang Jin Jun 2016

Corrosion-Induced Concrete Cracking Model Considering Corrosion-Filled Paste, Jianfeng Dong, Yuxi Zhao, Yingyao Wu, Weiliang Jin

International Conference on Durability of Concrete Structures

A TCP–TCL model is established to describe the relationship between the thickness of the corrosion-filled paste (CP) and that of the corrosion layer (CL). This model can describe the phenomenon that the corrosion filling in the concrete pores and accumulating at the steel/concrete interface occur synchronously. Based on the TCP–TCL model, a corrosion-induced concrete cracking model, which can quantitatively consider corrosion-filled paste at concrete/steel interface, is proposed. Combined with damage analysis in corrosion-induced cracking process of concrete cover, the model is developed to describe the quantity of steel corrosion required to crack …


The Compressive Strength Of Cement–Slag–Calcium Sulphoaluminate Ternary System, Hu Shi, Jun Wang, Zhuqing Yu, Xiaodong Shen Jun 2016

The Compressive Strength Of Cement–Slag–Calcium Sulphoaluminate Ternary System, Hu Shi, Jun Wang, Zhuqing Yu, Xiaodong Shen

International Conference on Durability of Concrete Structures

At present, there is an increasing interest on the use of calcium sulphoaluminate (C4A3$) in cement. In this paper, pure mineral of sulphoaluminate (C4A3$) was prepared in laboratory. Different dosages of steel slag and C4A3$ were blended into cement. The aim of this paper is to investigate the compressive strength of this ternary system. The test results show that the addition of C4A3$ can improve the strength of cement. Larger C4A3$ dosage (7%) may reduce the 28 days strength. The …


Potential For Alkali–Silica Reaction In Radiation Shielding Concrete Containing Special Aggregates, Daria Jóźwiak-Niedźwiedzka, Michał A. Glinicki, Karolina Gibas Jun 2016

Potential For Alkali–Silica Reaction In Radiation Shielding Concrete Containing Special Aggregates, Daria Jóźwiak-Niedźwiedzka, Michał A. Glinicki, Karolina Gibas

International Conference on Durability of Concrete Structures

In the present study, the potential for the alkali–silica reaction (ASR) in radiation shielding concrete containing special aggregates is presented. The tests were performed on two kinds of aggregate: (1) high-density aggregate to absorb the gamma radiation (barite, magnetite, and hematite) and (2) mineral with high bound water content to attenuate the neutron flux (serpentinite). The optical microscopy in transparent light on thin sections, XRD and XRF method, was used to assess the mineral composition of aggregates. ASTM C1260 test method for potential alkali reactivity of aggregates was applied also to investigate the effect of different content and crystal size …


Effect Of Superabsorbent Polymers (Sap) On Fresh State Mortars With Ground Granulated Blast-Furnace Slag (Ggbs), Fernando Do Couto Rosa Almeida, Agnieszka Joanna Klemm Jun 2016

Effect Of Superabsorbent Polymers (Sap) On Fresh State Mortars With Ground Granulated Blast-Furnace Slag (Ggbs), Fernando Do Couto Rosa Almeida, Agnieszka Joanna Klemm

International Conference on Durability of Concrete Structures

Although cementitious materials are the main construction materials and worldwide produced, there is still a major concern about their sustainability and durability, especially in terms of conserving resources, reducing wastes, and decreasing the environmental impacts of repair and replacement. In general, cementitious materials are very susceptible to cracking provoked by autogenous shrinkage due to their associated self-desiccation process. The problem is even more critical in concrete with blended cements, including Portland cement with ground granulated blast-furnace slag (GGBS). The current paper evaluates efficiency of superabsorbent polymers (SAP) as internal curing agents; shrinkage reduction in mortars with different levels of cement …


Designing Repeatable Self-Healing Into Cementitious Materials, Mo Li, Shuai Fan Jun 2016

Designing Repeatable Self-Healing Into Cementitious Materials, Mo Li, Shuai Fan

International Conference on Durability of Concrete Structures

Designing self-healing into cementitious materials can open a new world of opportunities for resilient concrete infrastructure under service loading conditions. The self-healing process should be robust as well as repeatable, allowing for self-repair after multiple damage events. The repeatability poses great challenges when self-healing strategies mainly rely on the formation of low-strength calcium carbonate healing product, complicated by the localized cracking behavior of cementitious materials. This study aims at formulating a new cementitious material system with designed physical and chemical characteristics that favour repeatable self-healing. Advanced experimental methods, coupled with micromechanics theory, are adopted to probe and design repeatable self-healing …


Progress In Durability Study Of Frp Materials, Zeng-Zhu Zhu, Ying-Wu Zhou, Li-Li Sui, Feng Xing, Jia Du Jun 2016

Progress In Durability Study Of Frp Materials, Zeng-Zhu Zhu, Ying-Wu Zhou, Li-Li Sui, Feng Xing, Jia Du

International Conference on Durability of Concrete Structures

During the past decades, FRP strengthened RC structures have attracted worldwide interest in both application and research. Nowadays, as more and more infrastructures are being suffered from severe corrosions due to harsh and extreme environments, the durability of FRP strengthened RC structures has generally emerged as the most important issue in research. Thus, the paper presents the latest progress in durability study of the FRP materials through an in-depth review and analysis on existing extensive investigations. The time-dependent performances of two types of FRP materials of carbon FRP (CFRP) and glass FRP (GFRP) under severe environments of humidity, high temperature, …