scholarly journals A State-of-the-Art Review on Core–Shell Pigments Nanostructure Preparation and Test Methods

Micro ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 55-85
Author(s):  
Kwok Wei Shah ◽  
Ghasan Fahim Huseien ◽  
Harn Wei Kua
Keyword(s):  
Building Materials ◽  
Elevated Temperatures ◽  
State Of The Art ◽  
Construction Materials ◽  
Test Methods ◽  
Core Shell ◽  
Coating Materials ◽  
Potential Core ◽  
Novel Technologies ◽  
Shell Nanostructures

Uses of novel technologies for improving the durability and lifespan of the construction materials have emerged as viable solutions toward the sustainable future wherein the coating industry plays a significant role in economy growth and better livelihoods. Thus, the continual innovation of various technologies to introduce diverse market products has become indispensable. Properties of materials like color stability under UV, elevated temperatures and aggressive environments, and skid and abrasion resistance are the main challenges faced by commercial coating materials, leading to more demand of natural materials as sustainable agents. Lately, nanostructured core–shell pigments with unique compositions have widely been utilized in composite materials to enhance their properties. Core–shell particles exhibit smart properties and have immense benefits when combined with building materials. Based on these facts, we comprehensively overviewed the state-of-the-art research of core–shell nanomaterials in terms of their preparation and performance evaluation methods, as well as feasible applications. The first part of this article discusses effective shell materials, including most common silica and titanium oxides. In addition, nanotechnology enabling the production and patterning of low-dimensional materials for widespread applications is emphasized. The second part deals with various potential core materials used to achieve core–shell nanostructures. The third part of this paper highlights some interesting mechanisms of core–shell structures in the modified systems that display high stability, durability, efficiency, and eco-friendliness. Finally, different applications of these core–shell nanostructures are underscored together with their test methods to evaluate their performances.

scholarly journals Fire Resistance Behaviour of Geopolymer Concrete:An Overview

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 82
Author(s):  
Salmabanu Luhar ◽  
Demetris Nicolaides ◽  
Ismail Luhar
Keyword(s):  
Compressive Strength ◽  
Thermal Resistance ◽  
Building Materials ◽  
Elevated Temperatures ◽  
Construction Materials ◽  
Flexural Behavior ◽  
Thermal Shrinkage ◽  
Physico Chemical ◽  
The Impact ◽  
Loss Of Strength

Even though, an innovative inorganic family of geopolymer concretes are eye-catching potential building materials, it is quite essential to comprehend the fire and thermal resistance of these structural materials at a very high temperature and also when experiencing fire with a view to make certain not only the safety and security of lives and properties but also to establish them as more sustainable edifice materials for future. The experimental and field observations of degree of cracking, spalling and loss of strength within the geopolymer concretes subsequent to exposure at elevated temperature and incidences of occurrences of disastrous fires extend an indication of their resistance against such severely catastrophic conditions. The impact of heat and fire on mechanical attributes viz., mechanical-compressive strength, flexural behavior, elastic modulus; durability—thermal shrinkage; chemical stability; the impact of thermal creep on compressive strength; and microstructure properties—XRD, FTIR, NMR, SEM as well as physico-chemical modifications of geopolymer composites subsequent to their exposures at elevated temperatures is reviewed in depth. The present scientific state-of-the-art review manuscript aimed to assess the fire and thermal resistance of geopolymer concrete along with its thermo-chemistry at a towering temperature in order to introduce this novel, most modern, user and eco-benign construction materials as potentially promising, sustainable, durable, thermal and fire-resistant building materials promoting their optimal and apposite applications for construction and infrastructure industries.

scholarly journals Sustainable Test Methods for Construction Materials and Elements

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 606 ◽  
Author(s):  
Ewa Szewczak ◽  
Agnieszka Winkler-Skalna ◽  
Lech Czarnecki
Keyword(s):  
Building Materials ◽  
Negative Impact ◽  
Construction Materials ◽  
Test Methods ◽  
Material Behavior ◽  
Sustainable Building ◽  
Methods Development ◽  
Test Models ◽  
Complete Test ◽  
The One

The laboratory testing of the construction materials and elements is a subset of activities inherent in sustainable building materials engineering. Two questions arise regarding test methods used: the relation between test results and material behavior in actual conditions on the one hand, and the variability of results related to uncertainty on the other. The paper presents the analysis of the results and uncertainties of the simple two independent test examples (bond strength and tensile strength) in order to demonstrate discrepancies related to the ambiguous methods of estimating uncertainty and the consequences of using test methods when method suitability for conformity assessment has not been properly verified. Examples are the basis for opening discussion on the test methods development direction, which makes possible to consider them as ‘sustainable’. The authors address the negative impact of the lack of a complete test models taking into account proceeding with an uncertainty on erroneous assessment risks. Adverse effects can be minimized by creating test methods appropriate for the test’s purpose (e.g., initial or routine tests) and handling with uncontrolled uncertainty components. Sustainable test methods should ensure a balance between widely defined tests and evaluation costs and the material’s or building’s safety, reliability, and stability.

scholarly journals Three decades of international RILEM activities to combat deleterious Alkali-Silica Reactions (ASR) in concrete.

2018 ◽  
Vol 199 ◽  
pp. 03001
Author(s):  
Børge Johannes Wigum ◽  
Jan Lindgård
Keyword(s):  
State Of The Art ◽  
Construction Materials ◽  
Performance Testing ◽  
Test Methods ◽  
Alkali Content ◽  
International Union ◽  
Field Exposure ◽  
Performance Based Assessment

Since 1988, the International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM) Technical Committees (TCs) have been seeking to establish universally applicable test methods for assessing the alkali-reactivity potential of aggregates, and from later on, for concrete mixes. TC 106 (1988 – 2001) focused on accelerated aggregate tests. The successor committee TC 191-ARP (2001 – 2006) also included work on diagnosis/appraisal & specification. TC 219-ACS (2006 – 2014) introduced work on performance testing & modelling. The major recommendations were published as a RILEM State-of-the-art Report in 2016. In 2014, TC 258-AAA was established, scheduling to finish the work on performance-based assessment in 2019. This current TC is focusing on the following Work Packages; WP1Performance based testing concepts, WP2 Relationship between results from laboratory and field and the establishment of field exposure sites, WP3 Testing of potential alkalis released from certain types of aggregates and measurement of internal concrete alkali content, and eventually; WP4 Verification of alkalis released from aggregates.

scholarly journals Self-Healing Construction Materials: The Geomimetic Approach

2021 ◽  
Vol 13 (16) ◽  
pp. 9033
Author(s):  
Valery Lesovik ◽  
Roman Fediuk ◽  
Mugahed Amran ◽  
Nikolai Vatin ◽  
Roman Timokhin
Keyword(s):  
Building Materials ◽  
Three Dimensional ◽  
Construction Materials ◽  
Evolutionary Stage ◽  
Self Healing ◽  
Building Science ◽  
Human Environment ◽  
Novel Technologies ◽  
Interdisciplinary Approaches ◽  
Wide Range

A person spends most of his life in rooms built from various building materials; therefore, the optimization of the human environment is an important and complex task that requires interdisciplinary approaches. Within the framework of the new theory of geomimetics in the building science of materials, the concepts of technogenic metasomatism, the affinity of microstructures, and the possibilities of creating composites that respond to operational loads and can self-heal defects have been created. The article aims to introduce the basic principles of the science of geomimetics in terms of the design and synthesis of building materials. The study’s novelty lies in the concept of technogenic metasomatism and the affinity of microstructures developed by the authors. Novel technologies have been proposed to produce a wide range of composite binders (including waterproof and frost-resistant gypsum binders) using novel forms of source materials with high free internal energy. The affinity microstructures for anisotropic materials have been formulated, which involves the design of multilayered composites and the repair of compounds at three levels (nano-, micro-, macro-). The proposed theory of technogenic metasomatism in the building science of materials represents an evolutionary stage for composites that are categorized by their adaptation to evolving circumstances in the operation of buildings and structures. Materials for three-dimensional additive technologies in construction are proposed, and examples of these can be found in nature. Different ways of applying our concept for the design of building materials in future works are proposed.

scholarly journals In situ TEM Investigation of Anti-sintering Au@Pt Core-shell Nanostructures on MoS2 at Elevated Temperatures

2018 ◽  
Vol 24 (S1) ◽  
pp. 1892-1893 ◽  
Author(s):  
Boao Song ◽  
Yifei Yuan ◽  
Soroosh Sharifi-Asl ◽  
Yuzi Liu ◽  
Reza Shahbazian-Yassar
Keyword(s):  
Elevated Temperatures ◽  
Core Shell ◽  
In Situ Tem ◽  
Shell Nanostructures

scholarly journals Mortars with Recycled Aggregates from Building-Related Processes: A ‘Four-Step’ Methodological Proposal for a Review

2021 ◽  
Vol 13 (5) ◽  
pp. 2756
Author(s):  
Federica Vitale ◽  
Maurizio Nicolella
Keyword(s):  
Building Materials ◽  
Thermal Analyses ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Research Trends ◽  
Mix Design ◽  
Recycled Aggregates ◽  
Design Parameters ◽  
Natural Aggregates ◽  
By Products

Because the production of aggregates for mortar and concrete is no longer sustainable, many attempts have been made to replace natural aggregates (NA) with recycled aggregates (RA) sourced from factories, recycling centers, and human activities such as construction and demolition works (C&D). This article reviews papers concerning mortars with fine RA from C&D debris, and from the by-products of the manufacturing and recycling processes of building materials. A four-step methodology based on searching, screening, clustering, and summarizing was proposed. The clustering variables were the type of aggregate, mix design parameters, tested properties, patents, and availability on the market. The number and the type of the clustering variables of each paper were analysed and compared. The results showed that the mortars were mainly characterized through their physical and mechanical properties, whereas few durability and thermal analyses were carried out. Moreover, few fine RA were sourced from the production waste of construction materials. Finally, there were no patents or products available on the market. The outcomes presented in this paper underlined the research trends that are useful to improve the knowledge on the suitability of fine RA from building-related processes in mortars.

scholarly journals Iron Based Core-Shell Structures as Versatile Materials: Magnetic Support and Solid Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 72
Author(s):  
Christian Zambrzycki ◽  
Runbang Shao ◽  
Archismita Misra ◽  
Carsten Streb ◽  
Ulrich Herr ◽  
...  
Keyword(s):  
Water Purification ◽  
Functional Materials ◽  
Core Material ◽  
Solid Catalyst ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
The Core ◽  
Shell Nanostructures ◽  
Sio2 Shell ◽  
Iron Based

Core-shell materials are promising functional materials for fundamental research and industrial application, as their properties can be adapted for specific applications. In particular, particles featuring iron or iron oxide as core material are relevant since they combine magnetic and catalytic properties. The addition of an SiO2 shell around the core particles introduces additional design aspects, such as a pore structure and surface functionalization. Herein, we describe the synthesis and application of iron-based core-shell nanoparticles for two different fields of research that is heterogeneous catalysis and water purification. The iron-based core shell materials were characterized by transmission electron microscopy, as well as N2-physisorption, X-ray diffraction, and vibrating-sample magnetometer measurements in order to correlate their properties with the performance in the target applications. Investigations of these materials in CO2 hydrogenation and water purification show their versatility and applicability in different fields of research and application, after suitable individual functionalization of the core-shell precursor. For design and application of magnetically separable particles, the SiO2 shell is surface-functionalized with an ionic liquid in order to bind water pollutants selectively. The core requires no functionalization, as it provides suitable magnetic properties in the as-made state. For catalytic application in synthesis gas reactions, the SiO2-stabilized core nanoparticles are reductively functionalized to provide the catalytically active metallic iron sites. Therefore, Fe@SiO2 core-shell nanostructures are shown to provide platform materials for various fields of application, after a specific functionalization.

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