Review
Polymer Science
Mand Kamal Askar, Yaman S. S. Al-Kamaki, Ali Hassan
Summary: Plastic waste is increasing, leading to concerns over the environment and waste disposal. Recycling plastic waste as green concrete can help reduce carbon dioxide emissions and address plastic waste disposal problems. Using PET as a replacement material in concrete construction has been studied to determine its effects on mixing design and concrete behavior.
Article
Chemistry, Physical
Katarzyna Kalinowska-Wichrowska, Edyta Pawluczuk, Michal Boltryk, Adam Nietupski
Summary: This article presents the physical and mechanical properties of geopolymer concrete with lightweight artificial aggregate. The influence of fly ash-slag mix as a pozzolanic additive and the molar concentration of sodium hydroxide solution were studied. The results showed that the most favorable parameters were a certain content of pozzolanic additives and a specific concentration of NaOH, which improved the compressive strength and reduced water absorption.
Review
Construction & Building Technology
Mohamed Sifan, Brabha Nagaratnam, Julian Thamboo, Keerthan Poologanathan, Marco Corradi
Summary: Lightweight high strength concrete (LWHSC) is gaining popularity due to its increased strength and reduced self-weight. This study comprehensively evaluated the material characteristics of LWHSC and found that the mechanical properties can be enhanced by strategically choosing the types and amounts of binder, water to binder ratio, fibers, and lightweight aggregate. Existing correlations used for conventional concrete need to be revised for LWHSC.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Jiaying Wei, Haoyang Liu, Christopher K. Y. Leung
Summary: Lightweight concrete is suitable for tall buildings and large structures, as well as the production of reinforced concrete units in modular construction. This study conducted an experimental program to develop a lightweight concrete mixture with a superior strength-to-density ratio by incorporating lightweight aggregate sourced from industrial by-products into foamed concrete. Scanning electron microscopy was used to understand the rationale behind the improvement.
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
(2023)
Article
Construction & Building Technology
Fahad K. Alqahtani, Ibrahim S. Abotaleb, Mohamed ElMenshawy
Summary: Recent research has developed methodologies to recycle plastic waste and use it as a replacement for natural aggregates in concrete, leading to savings in concrete and steel quantities and reductions in life cycle costs. The study further revealed that structures with certain slab spans benefit more from the use of LLDPE-based PLA, while smaller spans may not benefit financially. This research quantitatively validates the use of green recycled plastic aggregates to save natural resources and reduce life cycle costs.
JOURNAL OF BUILDING ENGINEERING
(2021)
Article
Chemistry, Physical
Ilenia Farina, Ivan Moccia, Cinzia Salzano, Narinder Singh, Payam Sadrolodabaee, Francesco Colangelo
Summary: This study investigates the recycling opportunities for industrial byproducts in innovative concrete manufacturing processes. The use of municipal solid waste incineration fly ash as a main component in artificially manufactured aggregates shows potential for producing lightweight concrete with good thermal performance. Substituting a percentage of recycled aggregates with recycled polyethylene terephthalate can further improve thermal conductivity. This type of concrete could have positive economic and environmental impacts by reducing the use of cement and lowering CO2 emissions.
Article
Construction & Building Technology
Pritam K. Pati, Shishir K. Sahu
Summary: This investigation focuses on producing lightweight fly ash angular aggregates (FAA) using local class 'F' fly ash in India and explores its potential as an alternative coarse aggregate in structural concrete applications. The FAA showed improved physical properties compared to commercially available fly ash pellets (FAP). Concrete containing FAA exhibited comparable strength parameters to conventional concrete, potentially due to the pozzolanic reaction between the fly ash angular aggregates and cement paste. The study suggests that FAA can be effectively utilized in RCC construction, reducing the dead load of structures while addressing fly ash disposal and mineral depletion issues.
ADVANCES IN CONCRETE CONSTRUCTION
(2022)
Article
Construction & Building Technology
Fahad K. K. Alqahtani
Summary: This study investigates the feasibility of using plastic-based manufactured aggregates in concrete. The results show that as the replacement ratio of manufactured aggregates increases, the slump of the concrete increases while the fresh density, compressive strength, and splitting tensile strength decrease. An equation for predicting the splitting tensile strength of concrete containing plastic-based aggregates is proposed in this study.
JOURNAL OF BUILDING ENGINEERING
(2022)
Article
Engineering, Civil
Shahram Jalali Mosallam, Hamid Pesaran Behbahani, Mehran Shahpari, Reza Abaeian
Summary: According to recent studies, nanoparticles, especially Carbon Nanotubes (CNTs), are the most effective additives for enhancing the mechanical properties of concrete. This study focused on exploring the impact of varying dosages of CNTs on the mechanical properties of lightweight concrete made with Structural Lightweight Expanded Clay Aggregates (LECA) as a substitute for coarse aggregates. It was found that incorporating 0.02% of the weight of cement in CNTs increased the compressive, tensile, and flexural strength of lightweight concrete by 29%, 44%, and 26% respectively after 28 days, while also reducing water absorption by 28.3%. However, higher concentrations of CNTs had a negative effect on the mechanical properties.
Article
Construction & Building Technology
Timo Haller, Nancy Beuntner, Henrik Gutsch, Karl-Christian Thienel
Summary: Infra-lightweight concrete (ILC) is a competitive alternative to multilayer wall structures commonly used today for monolithic exterior walls. This article presents the first study on the pumpability of ILC using common concrete pumps, demonstrating that ILC can be successfully pumped without significant negative effects on fresh or hardened concrete properties. The study highlights challenges in pumping ILC with highly porous aggregates and provides practical approaches to overcome them.
JOURNAL OF BUILDING ENGINEERING
(2023)
Review
Construction & Building Technology
Fernanda de Andrade Salgado, Flavio de Andrade Silva
Summary: The construction sector plays a vital role in economies and has a significant impact on the environment. The use of recycled aggregate has a dual environmental advantage in reducing natural resource consumption and waste disposal. However, it may slightly affect the workability and compressive strength of concrete, which can be addressed by removing adhered mortar or sealing pores. Studies have shown the feasibility of using recycled aggregate in structural elements.
JOURNAL OF BUILDING ENGINEERING
(2022)
Review
Construction & Building Technology
Marija Nedeljkovic, Jeanette Visser, Branko Savija, Siska Valcke, Erik Schlangen
Summary: This paper discusses the state-of-the-art of fine recycled concrete aggregates (fRCA), emphasizing the need for further research to introduce guidelines and tools for widespread application in new concrete, while highlighting the key physicochemical properties' impact on concrete performance.
JOURNAL OF BUILDING ENGINEERING
(2021)
Article
Construction & Building Technology
Hasan Jalilifar, Fathollah Sajedi
Summary: This study investigated the microstructure of 100% recycled concrete, finding that the addition of micro-silica significantly reduced pores and compressed the interfacial transition zone, making its microstructure similar to that of conventional concrete. On the other hand, the addition of fly ash and natural zeolite resulted in relatively porous and discontinuous microstructures in the concrete. Additionally, besides the poor mechanical properties, excessive discontinuities were observed in the interfacial transition zones of these concretes.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Construction & Building Technology
Jian-Xin Lu, Peiliang Shen, Hafiz Asad Ali, Chi Sun Poon
Summary: This study developed a high performance lightweight aggregate concrete by combining ultra high performance cementitious composite and different types of aluminosilicate lightweight aggregates. The incorporation of shale LWAs in the HPLAC led to higher strength and lower water absorption compared to clay LWAs, due to their fine pore structure and higher pozzolanic activity. The synergetic use of UHPC and pre-wetted shale LWAs produced an HPLAC with high structural efficiency, good thermal insulation, low autogenous shrinkage, and permeability.
CEMENT & CONCRETE COMPOSITES
(2021)
Review
Chemistry, Physical
Feng Huang, Shuai Zhou
Summary: This research summarizes the healing mechanisms and compositions of lightweight self-healing concrete (LWSHC), highlighting the importance of using lightweight aggregate (LWA) with interconnected pores and high strength to enhance crack closure rate and mechanical properties. Chemical healing agents, especially sodium silicate solution, are currently considered more effective than biological healing agents. Vacuum conditions, high-temperature processing, and coating technologies on LWAs can improve the healing effect of LWSHC.
