AN EXPERIMENTAL INVESTIGATION ON PLASTIC AND DEMOLISHED WASTE AS A PARTIAL REPLACEMENT IN CONCRETE MIX

Evaluation of strength characteristics and identifying the optimum dosage with the impact of partial replacement of recycled fine and coarse aggregate from construction and demolition waste

An experimentation made on plastic and demolished waste in concrete mix

The twenty-first century can be marked as a “plastic era” where different sectors are producing and consuming a huge amount of plastic. Concurrently, the plastic waste generation rate has been increasing and causing serious problems on the public health and ecosystem. Hence, recycling of plastic wastes can be one alternative management option for this peculiar waste stream. This study aims to evaluate the technical feasibility of plastic wastes as a partial replacement of coarse aggregate in a concrete mix using volcanic pumice as an admixture. Concrete test specimens prepared with standard M20 mix design were measured for a compressive and split tensile strength. Plastic aggregate made from plastic bags and bottles has shown a different degree of workability to replace the concrete mix. The compressive and split tensile strength tends to decrease with increasing the ratio of plastic aggregates for both types of plastics. However, the curve based operational cut-off value shows that the plastic bag and bottle aggregates can replace coarse aggregate from 11-14% and 35-37.5% respectively. Conclusively, utilizing the plastic aggregates as a partial replacement of coarse aggregate is technically feasible. However, applying the nominal concrete standard mix proportion is seemingly inappropriate while plastic aggregates used as an aggregate which in turn require a specific mix design. Despite the percent replacement is low, utilizing waste plastics in the concrete mix would help countries with the weak waste management system.

Conventional concrete mixes produced from naturally occurring aggregates offer benefits in strength, workability, volume stability and permeability, as well as a wide range of properties. However, with increasing availability of construction waste materials, such as demolished concrete and broken glass, there is the need to explore the feasibility of using recycled concrete and glass as replacement for natural crushed aggregates in Portland cement concrete, and determine their compressive and tensile strength in comparison with conventional concrete. Concrete specimens produced with varying percentages of replacement aggregates using recycled concrete and glass were tested for their workability, compressive strength and tensile strength. Six different concrete mixes were designed for the study, with percentage replacement of recycled concrete and broken glass of 0, 25, 50 and 75 by volume of natural aggregate in 1:2:4 concrete mix. In total, 54 cubes and 54 cylinders were cast for compressive strength and split tensile strength, respectively. Recycled concrete and broken / crushed glass were found to be good replacements for natural aggregates in concrete production, although the percentage by volume of recycled concrete and glass used in the concrete mix was an important controlling parameter. With regard to the workability of the concrete, it was found that recycled concrete and broken / crushed glass concrete had similar characteristics to conventional concrete mixes. Partially replaced recycled concrete and broken glass aggregates showed strength variation of between 15% to 30% from natural crushed aggregate concrete. It is recommended that concrete produced using recycled concrete and glass can be utilised for mass concrete works and structural members subjected to low loads.

Novel lightweight concrete containing manufactured plastic aggregate

The use of recycled aggregate in concrete is gaining much attention due to the growing need for sustainability in construction. In the present study, Self Compacting Concrete (SCC) is made using both natural and recycled aggregate (crushed recycled concrete aggregate from building demolished waste) and performance of recycled aggregate based SCC for the bond behaviour of reinforcement is evaluated. The major factors that influence the bond like concrete compressive strength (Mix-A, B and C), diameter of bar (Db=10, 12 and 16 mm) and embedment length of bar (Ld=2.5Db, 5Db and full depth of specimen) are the parameters considered in the present study in addition to type of aggregates (natural and recycled aggregates). The mix proportions of Natural Aggregate SCC (NASCC) are arrived based on the specifications of IS 10262. The mix proportions also satisfy the guidelines of EFNARC. In case of Recycled Aggregate SCC (RASCC), both the natural coarse and fine aggregates are replaced 100% by volume with that of recycled aggregates. These mixes are also evaluated for fresh properties as per EFNARC. The hardened properties like compressive strength, split tensile strength and flexural strength are also determined. The pull-out test is conducted as per the specifications of IS 2770 (Part-1) for determining the bond strength of reinforcement. Bond stress versus slip curves were plotted and a typical comparison of RASCC is made with NASCC. The fracture energy i.e., area under the bond stress slip curve is determined. With the use of recycled aggregates, reduction in maximum bond stress is noticed whereas, the normalised maximum bond stress is higher in case of recycled aggregates. Based on the experimental results, regression analysis is conducted and an equation is proposed to predict the maximum bond stress of RASCC. The equation is in good agreement with the experimental results. The available models in the literature are made use to predict the maximum bond stress and compare the present results.

Studies have proved that the mechanical properties of concrete, suddenly is dropped off with employing waste materials as replacements. The effectiveness of fibre addition on the structural stability of concrete has been indicated in recent investigations. There are different waste aggregates and fibres as plastic, rubber tire, coconut, and other natural wastes, which have been evaluated throughout the last decades. The fibres incorporation has a substantial effect on the properties of concrete mix subjected to different loading scenarios. This paper has reviewed different types of wastes and the effect of typical fibres including Poly Ethylene Terephthalate (PET), rubber tire, and waste glass. Furthermore, waste plastic and waste rubber has been especially studied in this review. Although concretes containing PET fibre revealed a reduction in compressive strength at low fibre fractions, using PET is resulted to micro-cracking decrement and increasing flexibility and flexural strength. Finally, according to the reviews, the conventional waste fibres are well-suited to mitigated time-induced damages of concrete and waste fibres and aggregates could be a reliable replacement for concrete.

Plastic is used in many forms in day-to-day life. Since Plastic is non-biodegradable, landfills do not provide an environment friendly solution. Hence, there is strong need to utilize waste plastic. This creates a large quantity of garbage every day which is unhealthy and pollutes the environment. In present scenario solid waste management is a challenge in our country. The production of solid waste is increasing day to day and causes serious concerns to the environment. In this study, the recycled plastics are used in the concrete as a partial replacement of fine aggregate in concrete. The main purpose of this study is to investigate the mechanical properties of concrete such as workability, compressive, flexural and split tensile strengths of concrete mixes with partial replacement of conventional fine aggregate with aggregate produced from plastic waste. The use of plastic aggregate as replacement for fine aggregate enhances workability and fresh bulk density of concrete mixes. The mechanical properties of concrete such as compressive, flexural, and tensile strengths of concrete reduced marginally up to 10% replacement levels.Plastic is used in many forms in day-to-day life. Since Plastic is non-biodegradable, landfills do not provide an environment friendly solution. Hence, there is strong need to utilize waste plastic. This creates a large quantity of garbage every day which is unhealthy and pollutes the environment. In present scenario solid waste management is a challenge in our country. The production of solid waste is increasing day to day and causes serious concerns to the environment. In this study, the recycled plastics are used in the concrete as a partial replacement of fine aggregate in concrete. The main purpose of this study is to investigate the mechanical properties of concrete such as workability, compressive, flexural and split tensile strengths of concrete mixes with partial replacement of conventional fine aggregate with aggregate produced from plastic waste. The use of plastic aggregate as replacement for fine aggregate enhances workability and fresh bulk density of concrete mixes. The mechanical properties of concrete such as compressive, flexural, and tensile strengths of concrete reduced marginally up to 10% replacement levels.

Study on green concrete replacing natural fine and coarse aggregate by plastic waste – An experimental and machine learning approach

Abstract: The production of plastic is increasing at a faster rate. It is very difficult to dispose this plastic waste as it creates environmental pollution. Plastic bottles usually take thousands of years to degrade and produce toxic fumes when incinerated. For solving this problem, construction industry can take a step to utilize this plastic waste as a substitute for aggregates. By replacing coarse aggregate as well as fine aggregate with waste plastic known as green innovation. As the years go by, waste plastic increases day by day, since most of the plastic used by human is non-bio-degradable. The idea behind this review is to identify research done by the researchers who uses recyclable material such as plastic obtained mostly from waste plastic that the people had generated around the world by utilisation of waste plastic in becoming of construction materials in order to overcome the environment problem that the society are facing. This paper aim to review the using of waste plastic to replace fine and coarse aggregate and stated the mechanical properties of the concrete. With different percentage replacement of aggregates will affect the different properties such as slump, compressive strength and ultimate strength of the concrete and compare with the control sample in order to find the suitable percentage of the waste plastic to replacement of aggregates for the concrete used. It was found that plastic as replacement for fine and coarse aggregate both have has lower compressive quality of the concrete, almost the same or lower slump test value for ordinary concrete and waste plastic concrete and lower density for the waste plastic concrete compare to the ordinary concrete.

The present study deals with fresh and hardened concrete properties of self-compacting concrete while carrying several trial mixes with a variety of water binder ratio and super-plasticizer content and finally achieved a trail mix with satisfying the flow properties as slump flow, V-funnel, and L-box test apparatus values are obtained within the limits of European guidelines. This study was carried out on the properties of Lightweight self-compacting concrete (LWSCC) with a binder content of 517 Kg/m3. In the achieved proportion of the final trail mix, the coarse aggregate will be replaced by Light Expanded Clay Aggregate (LECA) by varying the different percentages of coarse aggregate as 0%, 10%, 20%, 30%, 40%, and 50% by volume replacement. The fresh concrete properties are determined, and the values were found in considerable range as per European guidelines by performing slump flow, V-funnel, and L-Box tests for various proportions (0%, 10%, 20%, 30%, 40%, and 50%) of LECA aggregates by replacing normal coarse aggregates. The hardened concrete properties are determined by performing Compressive strength, split tensile strength, ultrasonic pulse velocity, and rebound hammer tests after curing specimens for 7 days and 28 days. Results indicate that LECA replacement in SCC up to 30% gives fair results in split tensile & compressive strength. NDT results show values are gradually decreasing with an increase in LECA proportion. Beyond 30% of LECA replacement in SCC gives results of split tensile, compressive strength, ultrasonic pulse velocity, and rebound hammer tests which are not inconsiderable range.

The growing consumption of natural river sand in concrete manufacturing has led to serious environmental degradation and material scarcity, emphasizing the need for sustainable substitute materials. Copper slag, a by-product generated during the copper smelting process, has emerged as a potential alternative to fine aggregate in high-strength concrete. This investigation examines the behavior of M60 grade concrete in which copper slag replaces natural sand at proportions of 0%, 20%, 40%, 60%, 80%, and 100%. The fresh concrete properties were assessed using slump cone tests, whereas the hardened properties were evaluated through compressive strength tests conducted at 7, 14, and 28 days, along with split tensile and flexural strength tests performed at 28 days. The experimental results revealed an increase in workability with rising copper slag content, attributed to its smooth surface characteristics and minimal water absorption capacity. The highest compressive strength was recorded at a 40% replacement level, showing noticeable improvement over the conventional mix. However, replacement levels exceeding 60% resulted in a reduction in strength due to increased free water content and weaker interfacial bonding between the paste and aggregates. Similar performance patterns were observed for split tensile and flexural strengths, with optimal results obtained within the 40–60% replacement range. The study concludes that copper slag can effectively substitute up to 60% of natural sand in M60 grade concrete without adversely affecting structural performance, thereby supporting sustainable construction and efficient utilization of industrial waste.

Effect of waste electronic plastic and silica fume on mechanical properties and thermal performance of concrete

Environmental concerns on the impact of sand dredging in India have led to severe restrictions on this activity, with direct impact on concrete construction. At the same time, waste plastic is rarely recycled, and left untreated in open landfill. Work funded by the British Council under the UKIERI (United Kingdom India Educational Research Initiative) programme, has been investigating how recycled plastic might be used as a replacement for sand in concrete, providing a solution to both problems. This paper details 180 day carbonation tests under accelerated conditions in a 4% CO2 environment, comparing concrete with 10% sand replaced by recycled plastic with a plain concrete mix. The accelerated test method is estimated to predict the performance of the material after 25.7 years in service. It is seen that the carbonation depth after 180 days is only 5% greater in the concrete with recycled plastic.

Sulfuric acid resistance of concrete containing coal waste as a partial substitute for fine and coarse aggregates