Recycling Of Construction Waste Research Articles

Optimization and Prediction of Concrete with Recycled Coarse Aggregate and Bone China Fine Aggregate Using Response Surface Methodology

Construction recycled material is crucial for protecting natural resources and promoting sustainable human development in a rapidly industrializing world. Many administrations worldwide accepted that it is beneficial to use demolition waste in the concrete building industry to reduce manufacturing costs and minimize the use of virgin aggregates. However, control measures should be done as their mechanical properties are poorer than traditional aggregates. To overcome this problem, pozzolanic materials like bone chine can be incorporated, providing extra CSH gel, which improves mechanical strength. Therefore, this research is aimed at producing eco‐friendly concrete, which can be used for medium‐grade strength, using recycled construction waste (RCA) as coarse and bone china fine aggregate (BCA) as fine aggregate. Workability, density, compressive, split tensile, and flexural strength are used to compare the fresh and hardened properties of the concrete. Experimental and statistical research is employed in the current study to evaluate the impact of RCA and BCA on the performance of concrete. To simulate all measurable responses, including workability, density, compressive, flexural, and split strength, RSM (response surface methodology) was utilized. The CCD (Central Composite Design) approach in RSM was used to create and analyze mixes in an experiment. Based on the experiment’s results, mathematical models were designed and assessed using the analysis of variance test (ANOVA). The analysis of variance results demonstrated the statistical significance of each constructed model. Three‐dimensional response surface plots created using established regression models were used to investigate the interaction between the respective variables and to optimize the mixing ratio. The results indicate that the optimum utilization of RCA is up to 40% and BCA up to 60% as coarse and fine aggregate replacement in concrete, respectively, which not only helps to reduce costs but also offers sustainability. Finally, it was concluded that the generated models might be employed by obtaining the maximum tested features of concrete to assure a quick mix design approach. To conduct the microstructure study, thin section techniques were used to observe a strong aggregate‐matrix interaction.

Review on Properties of Recycled Construction Waste Concrete Aggregate

Recycled construction waste aggregate is to solve the damage caused by construction waste to the natural environment. Through crushing, screening and other processes, the construction waste aggregate is made into reusable coarse aggregate or fine aggregate, and then replaced by natural gravel or natural sand and stone in different replacement rates and applied to the recycled aggregate in concrete. In this paper, three main physical properties of waste concrete, the old ceramic tile, broken ceramic, crushed clay brick and waste glass aggregate are summarized, which are water absorption rate, apparent density and crushing index of recycled building waste aggregate. The crushed clay brick and broken ceramic aggregate have the highest water absorption rate and low in apparent density and high in crushing index. Waste concrete mixture has excessive water absorption, low apparent density and excessive crushing index, whilst damaged ceramic tile combination has low water absorption, low apparent density and low crushing index.

Geotechnical assessment and large scale direct shear testing on recycled brick aggregates

The current scenario of handling and recycling of construction and demolition (C&D) waste in India is not very promising. The proper management of C&D waste material is necessary to achieve sustainability goals in the field of Civil Engineering. In this research, the utility of recycled brick aggregates (RBA) in geotechnical applications is assessed by performing an extensive experimental program which includes tests like: particle size distribution, specific gravity, water absorption, modified proctor compaction, relative density, aggregate crushing, slake durability index, aggregate impact and Los Angeles abrasion. Shear strength parameters of RBA are evaluated by performing large scale direct shear test (DST). Source of origin of recycled brick aggregates (RBA) for the present study is MNIT campus, Jaipur. The RBA are found to have good compaction and shear strength characteristics as the values of maximum dry density (MDD), optimum moisture content (OMC), cohesion (c’) and angle of shearing resistance (Ф’), evaluated as 2.03 gm/cm3, 11.52 %, 55.82 kPa and 68° respectively. The large scale DST results are also compared with the available literature. The RBA are found to have susceptibility towards crushing failure, thus this study concludes that the RBA may provide good performance as a base/sub-base or backfill material only under the light loading conditions like: - footpath sub-base, light traffic loading road base and sub-base etc. It is recommended that the incorporation of geosynthetic reinforcements or some durable C&D waste aggregates in RBA may enhance its applicability as a sub-base material under heavy traffic pavements.

Effect of Recycled Mixed Powder on the Mechanical Properties and Microstructure of Concrete

In this paper, recycled bricks and recycled concrete were applied to prepare eco-friendly recycled mixed powder (RMP) cementitious material, as a supplementary to replace conventional cement for improve the recycling of construction and demolition waste. Based on the effect of cementitious materials on the hydration of silicate cement, the effects of RMP on the workability, mechanical properties and microstructure of recycled mixed powder concrete (RMPC) with the different replacement ratios and the 8:4 and 6:4 mixing ratio of recycled brick powder (RBP) and recycled concrete powder (RCP) were investigated. The results showed that the fluidity of the mix decreased with increasing of the replacement ratio and the mixing ratio of RBP and RCP, but the influence of the fluidity was smaller within 15% replacement ratio. As the replacement ratio increases, the internal pore structure of RMPC tends to be loose and porous, which exhibits a significant pore volume distribution characteristic. The number of large capillaries was considerably increased at replacement ratio of 45%. The 7 d compressive strength of RMPC was slightly lower than that of ordinary concrete. The compressive and splitting tensile strengths of RMPC at 28 d increased by 4.2% and 10.1%, respectively, with increasing curing age at 15% replacement ratio and 6:4 mixing ratio. The RMPC mechanical strengths with RBP and RCP at the mixing ratio of 6:4 was higher than those of 8:2. Finally, a basis for the recycling of RBP and RCP in the construction industry can be provided by the results of this study.

Determinants of Contractor's Construction and Demolition Waste Recycling Intention in China: Integrating Theory of Planned Behavior and Norm Activation Model

Determinants of Contractor's Construction and Demolition Waste Recycling Intention in China: Integrating Theory of Planned Behavior and Norm Activation Model

Проблемы переработки строительных отходов при строительстве и реконструкции жилых зданий

At present, only 10-15% of the total volume of construction waste is recycled in Russia. Most of the waste has to be buried in special landfills, the capacity of which is almost exhausted. The reasons of low volumes are the following: slow re-equipment process of recycling enterprises; imperfection of legislative base for regulation of relations in the field of operation; lack of state support and economic incentives in the field of construction waste recycling. These problems could be solved by means of providing tax benefits, loans with reduced rates, subsidies from the budgets of different levels so as to implement resource- and energy-saving projects in the field of recycling construction waste and its use as raw material in the production of construction materials with low cost and improved quality characteristics, in order to use it in civil, industrial and road construction, within the mechanism of public-private partnership based on concession.

Behaviour of sustainable slag enriched concrete: Effect of fully replacement of natural coarse aggregate with construction waste

In construction domain and especially making concrete, the wise exploitation of natural resources along with the incorporation of recycled construction waste are solutions for making concrete an environmentally friendly construction material. This investigational study examines the performance of recycled aggregate concrete (RAC) made fully from recycled coarse (RC) aggregate. Only one mix made with natural coarse (NC) aggregate was prepared as a control for comparison purposes. The fresh concrete workability, the hardened concrete mechanical properties and the dynamic modulus of elasticity (Ed) were investigated. The impact of utilizing ground granulated blast furnace slag (GGBFS) as a replacement of cement at contents of 5%, 10%, 15%, and 20% on RAC performance was evaluated as well. Six mixes (two with no GGBFS and four with GGBFS) were prepared for measuring RAC behaviour. The findings of this study disclose that the workability (slump test values) decreases when GGBFS partially replaced cement in the mixes made fully with RC aggregate. A reduction of 26% in slump was observed when NC aggregate fully replaced with RC aggregate keeping cement without replacement and also in case of replacing only 5% of cement by GGBFS. Further reduction in slump was noticed when cement replacement by GGBFS increases in which the reduction reaches 43% for 20% replacement. Nevertheless, GGBFS can make a significant enhancement in concrete compressive strength as it almost reached 97% of NC aggregate concrete strength when 20% of cement replaced with GGBFS in the mix. The same positive effect of replacing cement with GGBFS was noticed in Ed results of concrete as well as resulted in slight enhancement in the density of the RAC.

Evaluation method of solid construction waste recycling capacity based on AHP-fuzzy algorithm

Evaluation method of solid construction waste recycling capacity based on AHP-fuzzy algorithm

Evaluation method of solid construction waste recycling capacity based on AHP-fuzzy algorithm

Evaluation method of solid construction waste recycling capacity based on AHP-fuzzy algorithm

Sustainable Management of Construction and Demolition Waste

Abstract: Construction activity in India has magnified well within the past decade. Likewise, there has conjointly been a proportion to rise within the generation of construction and demolition waste (C&DW). This, alongside the fact that in India the speed of recycling and reuse of C&DW continues to be quite low and has engendered a heavy environmental downside and a motivation to develop ways and management plans to resolve it. Almost every time the construction and demolition waste end up settling in landfills disrupting the environmental, economic, and social life cycle. Its composition has a significant potential to reuse or recycle C&DW, and thereby, contribute to enhancing the sustainability of construction, however, practical procedures don’t seem to be widely known or practiced within the construction industry. Elements of construction and demolition waste generally embrace concrete, asphalt, wood, metals, roofing, paper, plastic, drywall, and glass. Sustainable development defines as accomplishing the current requirements without compromising the ability of future generations to satisfy their own needs and can be thought of as one of the concrete solutions to resolve construction and demolition waste downside. Sustainable development in construction can facilitate plenty to cut back the issues associated with the environment and natural resources as the construction industry is among the major user of the world’s resources. Sustainable design, correct use, and reuse of the resources/construction materials can create the construction industry a lot more economical and greener. There’s conjointly a large demand for natural aggregates within the construction sector with a big gap in its demand and supply, which may even be reduced marginally by the employment of recycling and reuse of construction and demolition waste. Correct handling, storage, and treatment of C&D waste not only solely forestall degradation of Mother Earth but even have an important impact on sustainability using reducing the usage of natural resources. The paper covers various issues associated with the reusing and recycling of C&D waste, which needs restrictive mechanisms and procedures to be followed for achieving the aim of sustainability in the construction industry.

Indoor Nanoparticle Characterization in Construction Waste Recycling Companies over Time

Building activity is a significant source of atmospheric contamination by ultrafine dust. Cognizant of this fact, those active in the use and recycling of construction materials must be aware of the risks associated with exposure to nanoparticles (NPs) and ultra-fine particles (UFPs), as well as the associated health impacts. This work analyzed NPs and UFPs generated in a small building-material recycling company using high-resolution electron microscopes and X-ray Diffraction. A self-made passive sampler (LSPS) that can obtain particulate samples without physical and morphological changes, especially where there is a suspension of particulate material, was used in this study. A total of 96 particulate samples, using the LSPS for three months in four seasons, were collected during the study. Thus, the dry deposition of the particles, which are considered highly harmful to human health, was found in each of the four seasons of the year. It is suggested that for future research, the toxicological evaluations of the particulates in the construction industry should be investigated through the consideration of measures to control and mitigate the health risks of workers regarding exposure to NPs and UFPs.

Academician L. A. Vaisberg’s contribution to advancement in coal beneficiation

Coal as one of the main strategic materials has always been an objective of scientific thought for many scientists. To date, coal is still competitive with hydrocarbon sources. The coal industry is developing in its own way and remains a priority for many countries. This is due, first, to the use of coking coals for the metallurgical industry, for which there is, as of today, no alternative. The existing huge resources and the newly discovered coal deposits in Russia are the impetus for the development of new beneficiation and deep processing technologies. The research in the field of coal beneficiation using dry processing methods is ongoing in Russia and worldwide, thanks to the fundamental foundations laid by the great modern scientist Leonid Abramovich Vaisberg. The development of scientific and methodological framework for the dry coal beneficiation processes has always been one of the priorities of Mekhanobr-Tekhnika Research and Engineering Corporation and its Head Academician of RAS L.A. Vaisberg. In the framework of XVIII International Congress on Coal Preparation (ICPCI-2016) in Saint Petersburg, held by the Mining University, and during the further work in India and Australia, a large amount of joint research work was carried out. Leonid Abramovich remained a member of the International Organizational Committee (IOC) for 5 years and until his last days, and team-worked with the staff of the Mining University. This gave a strong impetus to the development and continuation of coal-related research in the University’s scientific environment. Leonid Abramovich Vaisberg, Doctor of Engineering Sciences, Professor, Academician of the Russian Academy of Sciences, a leading specialist in Russia in the field of mineral and mining waste management, mining engineering, theory of design, as well as operation of vibrating machines and devices used in mining, construction, industrial and municipal waste recycling has made a huge contribution to the development of the international and national coal industry.

Influence of Recycled Concrete Powder (RCP) and Recycled Brick Powder (RBP) on the Physical/Mechanical Properties and Durability of Raw Soil

The influence of recycled concrete powder (RCP) and recycled brick powder (RBP) on the dry density, optimal water content, and compressive strength of raw soil materials was investigated in this study. Moreover, the following resistance of freeze–thaw cycles was also considered. Additionally, X-ray diffraction (XRD) and scanning electron microscope (SEM) were selected to detect its mineral composition and observe the microstructure, further revealing the mechanism of performance change. The mass ratios of recycled concrete powder and recycled brick powder were 2~14%. Results showed that the dry density decreased and the optimal water content increased with the increasing dosage of recycled concrete powder and recycled brick powder. When the dosage of RCP or RBP was lower than 14%, raw soil with RCP showed higher optimal water content and lower dry density. However, when the dosage was higher than 14%, the result was the opposite. The addition of recycled concrete powder and recycled brick powder was able to decrease the compressive strength of raw soil, except for 10% of recycled brick powder. Raw soil with recycled brick powder presented higher compressive strength than that of raw soil with recycled concrete powder. RBP could improve the freeze–thaw cycles’ resistance of specimens; however, RCP led to decreasing the resistance of freeze–thaw cycles. These research findings can provide reference to the recycling of construction waste.

Properties and activation modification of eco-friendly cementitious materials incorporating high-volume hydrated cement powder from construction waste

Utilizing hydrated cement powder (HCP) as alternative binder in new cementitious materials provides a new way of recycling construction waste, while the relatively low activity of HCP limits its application to some extent. This work investigated the properties and heat activation modification of mortar including high-volume HCP. The HCP with irregular micro-structure mainly contains C-S-H gel, calcium hydroxide, calcite and quartz, and the incorporated HCP in cementitious materials reduces the number of new hydration products. The HCP after heat activation appears new active components (such as calcium silicate and calcium oxide), and the addition of such heat-activated HCP improves the micro-structure and helps the hydration reaction of new paste. The nanoindentation test highlights that the elasticity modulus and indentation hardness of paste including heat-activated HCP are higher relative to paste including untreated HCP. The activity index of HCP ranges from 73.63% to 91.81% as the modification temperature increases from 20 °C to 600 °C. Incorporating high-volume HCP is detrimental to the mechanical strength and transport properties of newly-prepared mortar, and the compression strength and capillary absorption coefficient of mortar with 50% HCP is approximately 50% lower and 193.7% higher relative to plain mortar. The activation modification of HPC reduces its adverse impact on performance of newly-prepared mortar, and the performance of mortar including HCP after 400–1000 °C activation is obviously better relative to mortar with untreated HCP. Based on the micro-characteristics, mechanical performance and transport properties, 600–800 °C activation temperature is recommended in modify the performance of cementitious materials incorporating high-volume HCP.

Development and characterization of lightweight aggregate recycled from construction and demolition waste mixed with other industrial by-products

The amount of construction and demolition waste and industrial by-products are increasingly high in Vietnam recently. The recycling of these wastes as new construction materials is an effective solution for sustainable development. This paper presents a method for the recycling of construction and demolition waste and other industrial by-products, such as fly ash and slag in Vietnam to produce lightweight aggregate . Experimental results show that masonry wastes including brick and mortar as well as fly ash are suitable materials for producing lightweight aggregates with a granule density of less than 1000 kg/m3 with the optimum sintering temperatures and the residence time in the range from 1220 °C to 1250 °C and, 6 to 9 min, respectively. These recycled lightweight aggregates can be used as valuable substitutes for natural aggregates to make lightweight concrete for new structures and therefore contribute to the construction industry's sustainability.

Development of Concrete Incorporating Recycled Aggregates, Hydrated Lime and Natural Volcanic Pozzolan

Recycling of construction and demolition waste is a central point of discussion throughout the world. The application of recycled concrete as partial replacement of mineral aggregates in concrete mixes is one of the alternatives in the reduction of pollution and savings in carbon emissions. The combined influence of the recycled crushed concrete, lime, and natural pozzolana on the mechanical and sustainable properties of concrete materials is firstly proposed in this study. In this research, unconventional construction materials are employed to produce concrete: the recycled crushed concrete is used as coarse aggregate, while lime and natural pozzolana are used as a partial replacement for cement. Substitutions of 10%, 20%, 50% of gravel are made with recycled aggregates, and 2%, 5%, 10% of cement with lime and natural pozzolan. Tests on the fresh and hardened properties, destructive (compressive strength) and non-destructive tests (sclerometer rebound and ultrasound) of mixtures are carried out. It is shown that the use of recycled materials can provide an increase in compressive strength of up to 34% with respect to conventional concrete. Life cycle cost and sustainability assessments indicate that concrete materials incorporating recycled aggregate possess good economic and environmental impacts.

Assessment of bearing capacity and settlement characteristics of soft soils reinforced by crushed concrete and sodium silicate columns

Various building infrastructure projects around the world have resulted in a major rise in waste materials production such as concrete, fly ash, plastic, rice husk, foundry sand, and other materials, raising disposal issues. In soft clay, stone columns are a traditional ground improvement technique. Crushed concrete is abundant and comes from the removal of old buildings as well as waste concrete from new construction. As a result, construction waste recycling is important, both in terms of reducing the amount of open land needed for landfilling and in terms of environmental protection by resource conservation. Laboratory tests were conducted in this research to examine the influence of crushed concrete columns and crushed concrete by adding 6% sodium silicate columns on characteristics of soft soils (kaolin soil). The finding was that adding sodium silicate to crushed concrete gave a better degree of improvement as compared with crushed concrete columns in both cases (flouting and end bearing). But in flouting case show bearing ratio increased by 367% and in end bearing case increased by 611% as compared with bearing ratio of untreted soil at failure.

Explore potential barriers of applying circular economy in construction and demolition waste recycling

The circular economy (CE) aims to reduce resource input and systematically avoid or reduce waste. In addition, the CE is an essential framework for achieving sustainable development. Understanding the barriers to construction and demolition waste (C&DW) recycling development under the CE model can promote sustainable C&DW management. This study used social network analysis (SNA) to explore the potential barriers, extent and key stage of the transition to CE for C&DW recycling in Guangzhou, China. The results show the following: 1) The network was loose and did not show a clear trend towards a certain point, indicating that the development of current C&DW recycling shows a lack of effective management mechanisms to control and constrain the barrier factors. 2) The key barriers to the network include inadequate incentives from the government sector, inadequate supportive policies, insufficient publicity and education on the recycling of C&DW, and an inadequate legal framework for the management of C&DW. The key stage of the “control power” and “adjustment ability” is the promotion and application of recycled products. 3) The network had three core cluster positions. The authors proposed corresponding suggestions for the results, which will provide theoretical guidance for policy-making for the transition of recycling C&DW move to CE, enabling timely advancement of CE initiatives in the construction industry.

A Review of Carbon Footprint Reduction in Construction Industry, from Design to Operation.

Construction is among the leading industries/activities contributing the largest carbon footprint. This review paper aims to promote awareness of the sources of carbon footprint in the construction industry, from design to operation and management during manufacturing, transportation, construction, operations, maintenance and management, and end-of-life deconstruction phases. In addition, it summarizes the latest studies on carbon footprint reduction strategies in different phases of construction by the use of alternative additives in building materials, improvements in design, recycling construction waste, promoting the utility of alternative water resources, and increasing efficiencies of water technologies and other building systems. It was reported that the application of alternative additives/materials or techniques/systems can reduce up to 90% of CO2 emissions at different stages in the construction and building operations. Therefore, this review can be beneficial at the stage of conceptualization, design, and construction to assist clients and stakeholders in selecting materials and systems; consequently, it promotes consciousness of the environmental impacts of fabrication, transportation, and operation.

Static Hardness Testing of Cement Mortars Containing Different Types of Recycled Construction Waste Powders

The present paper deals with the hardness of cement mortars prepared with recycled materials that are potential supplementary cementitious materials (SCM). Two potential SCMs (aerated concrete powder (ACP) and concrete powder) were investigated and compared with a reference (neat cement) sample and a sample containing metakaolin (MK). The long-term performance of the mortars was studied up to the age of one year. Based on the compressive strength tests at different ages, neither concrete powder nor ACP significantly decreases the compressive strength at a 10% substitution ratio. The samples were studied with two types of static hardness tests: the Brinell hardness test and the depth sensing indentation test at two different load levels. The hardness test results indicated that the standard deviation of the results is lower at a higher load level. In the case of metakaolin and concrete powder, the change in the compressive strength was observable in the hardness test results. However, in case of the ACP, the compressive strength decreased, while the hardness increased, which can be traced back to the filler effect of aerated concrete powder. Finally, using the DSI test, the hardness results were analyzed on an energy basis. The analysis highlighted that the change in the hardness is connected to the elastic indentation energy, while it is independent from the dissipated (plastic) indentation energy.