Green Concrete Production Research Articles

Green concrete composites production comprising metalized plastic waste fibers and palm oil fuel ash

Amongst the potential solutions to a cleaner environment is to minimize the consumption of non-biodegradable materials and to reduce wastes. The generation and disposal of waste plastics cause severe impacts on the environment. The utilization of solid waste in the sustainable constructions has concerned much attention due to the lower cost of wastes along with saving a necessary place of landfills. In this paper, the feasibility of metalized plastic waste (MPW) fibers and palm oil fuel ash (POFA) in the production of concrete composites was investigated by assessing the mechanical properties and ultrasonic pulse velocity. Six concrete mixes containing MPW fibers varying from 0 to 1.25% with a length of 20 mm were made of ordinary Portland cement (OPC). A different six concrete mixtures with the same fiber content were made, where 20% POFA substituted OPC. The results show that MPW fibers, together with POFA reduced the workability of concretes. It has also been found that by adding MPW fibers to the concrete mixtures, the compressive strength decreased for both OPC and POFA mixes at the early ages. Though at the curing period of 91 days, the mixes contain POFA attained compressive strength higher than those of OPC mixes. The mixture of MPW fibers and POFA subsequently enhanced the tensile and flexural strengths, thereby increasing the ductility. The study revealed that the MPW fibers are potential to be used in sustainable concrete by improving the mechanical properties.

EFFECT OF RECYCLED CONCRETE AGGREGATE QUALITY ON PROPERTIES OF CONCRETE

ABSTRACTThe possibility of the use of recycled aggregates from the construction industry in green concrete production is of increasing importance to reduce the negative environmental impact associated with construction and demolition wastes. The objective of this study is to investigate the effect of recycled concrete aggregate (RCA) quality on the properties of hardened concrete properties such as compressive strength, splitting tensile strength, density, water absorption capacity and porosity accessible to water. The RCA used in this study was obtained from the crushing of waste concrete with two different compressive strengths (LRCA obtained from the crushing of waste concrete having compressive strengths below 30 MPa and HRCA obtained from the crushing of waste concrete having compressive strengths above 30 MPa). The natural coarse limestone aggregate was 100% replaced with coarse LRCA and HRCA. As a result of the study, the use of 100% HRCA and %100 LRCA instead of limestone coarse aggregate in the concrete adversely affected its mechanical and physical properties. In addition, HRCA showed better performance in terms of compressive strength, tensile strength, water absorption and porosity compared to the use of LRCA. Furthermore, the percentage of adhered mortar on the surface of LRCA and HRCA was analyzed using a computerized micro tomography device, and it was found that the percentages of attached mortar and aggregates are 61% and 35.5% for LRCA, whilst the attached mortar and aggregate contents for HRCA are 45.9% and 53.7%, respectively.

A sustainability comparison between green concretes and traditional concrete using an emergy ternary diagram

The sustainable development of green concrete consumes as few natural resources as possible during production and uses and utilizes recyclable waste materials as raw materials. This study summarizes three modes of green concrete production: recycled aggregate concrete production mode, fly ash concrete production mode, and circular economy concrete production mode, as well as the system emergy flow of each mode of production, and presents emergy analysis methods for each mode. With the help of emergy ternary diagram auxiliary lines, the emergy ternary diagram expressions of three green concrete production modes and traditional concrete production modes are analyzed, respectively. The ternary diagram of emergy analysis directly reflects the resource allocation of the system. The relationship between the emergy utilization ratio and the indicators of the system is analyzed, and the sustainability of the existing concrete production system is evaluated comprehensively. The R-resource line corresponds to the environmental load ratio. The closer the R-resource line is to the F-axis, the greater the environmental pressure of the system. The N-resource line corresponds to emergy yield ratio and emergy investment ratio. The closer the N-resource line is to the N-axis, the greater the energy input-output efficiency of the system. The closer the N-resource line is to the “0” point of the R-axis, the higher the utilization rate of outsourced resources. In the emergy ternary diagram, it is evident that the circular economy concrete production mode is more sustainable than the other three concrete production modes. Combined with the analysis of the sensitivity line and sustainability line, it is predicted that the concrete production mode along the direction of the R-Sensitivity line is a sustainable development path.

Sustainable Concrete Containing Recycled Aggregates and Pozzolana in Sudan

Sustainable trails in the building industry called for preserving the natural resources through the production of green concrete. This is concrete where waste materials are used as at least one of its components, or its production does not lead to environmental destruction through the reduction, reuse or recycling techniques. Experimental results from a study on the potential usefulness of recycled coarse aggregates (RCA) blended with locally available natural Pozzolana are outlined in this paper. Eight concrete mix scenarios were considered: a standard mix with 100% natural coarse aggregates (NCA), 25% RCA, 50% RCA, 75%RCA, 100% RCA and no Pozzolana, 100% RCA and 10% Pozzolana, 100% RCA and 20% Pozzolana, 100% RCA and 30% Pozzolana. Slump test was conducted and the results were all within the specific limits. It was conversely realized that the workability decreased in the cases of replacing NCA by RCA with no Pozzolana while an increase was recognized when the Pozzolana was add in the different percentages with the best results achieved with 100% RCA and 20% Pozzolana. The compressive strength results were consistent for the different curing ages with the highest strength being acquired with the mix that contained 100%RCA and 10% Pozzolana. The results of the durability test revealed better values for the wave length speed value when the NCA was replaced by the RCA. Considering these outcomes, the optimum result was achieved in the case of 100%RCA and 10%Pozzolana. Thus, the experimental results offer good indication for a potential usefulness of RCA proposing a reasonable way for preserving virgin natural materials.

Emergy Evaluation of Green Concrete Production Efficiency

By comparing the traditional concrete production mode with green concrete production mode, including recycled aggregate concrete production mode and fly ash concrete production mode, the system emergy flow of each production mode is analyzed, and the emergy analysis method for each mode is put forward.

Mathematical Simulation of Bottom Ash Effect and Expanded Polystyrene on the Polystyrene Concrete Properties

Nowadays various light concrete types have many advantages as compared to heavyweight concrete (total structures mass decrease, increased thermophysical properties, less material consumption). Various industrial wastes use such as fly ashes, slag and bottom ash was suggested to enhance the light concretes effectiveness. This is greatly important for a green light concrete production since it is very important to obtain new types of environmentally friendly materials using wastes. The article substantiates the light concrete use and creation with organo-mineral additives based on industrial waste, analysis of the second-order mathematical model describing the bottom ash (BA) amount effect of Vung Ang TPP and expandable polystyrene spheres (EPS) on the light concrete density and compressive strength at the age of 28 days of normal hardening is done. In this work, the BA and EPS amounts varied from 14.5 to 45.5%, respectively, of the cement weight and from 24.5 to 55.5% of the concrete mix volume. The effect of expanded polystyrene spheres (EPS) and bottom ash (BA) TPP "Vung Ang" amounts as the input parameters on the polystyrene concrete properties (PCP) were investigated in this study. On the one hand, various proportions of BA (14.5, 20, 30, 40 and 45.5%) were blended in concrete mixes as partial weight replacement for Portland cement. On the other hand, EPS amount was replaced by the fresh concrete volume in the range from 24.5% to 55.5%. Additionally, the central composite design method of Box-Wilson for second order factors was used to predict the EPS and BA effects on the polystyrene concrete properties. The results showed that the proposed regression equations of this mathematical model achieved an adequate prediction accuracy. Hence, the effects of both bottom ash contents and expanded polystyrene spheres on the dry density and 28-day compressive strength of the PSC-specimens were significant. In the future, further investigations have to be carried out to study the quality prediction of green light concrete containing various wastes.

Studies Undertaken to Incorporate Granite Wastes and Fly Ash in Green Concrete Production

Studies Undertaken to Incorporate Granite Wastes and Fly Ash in Green Concrete Production

Research on Eco-friendly Alkali Activated Concrete Incorporating Industrial Wastes

In the present scenario, the production of green and sustainable concrete has become a must to substitute the ordinary Portland cement (OPC) concrete. It is an eminent fact that the manufacture of OPC requires burning of its raw materials which lead to a huge amount of carbon dioxide liberation; thus it requires a large amount of energy dissipation. The concrete produced using alkali activation has become renowned methods to replace the conventional OPC, which gives an answer to find a way to produce environmentally friendly concrete. In the current study, the alkaline activator used to activate the binder was sodium hydroxide solution dispersed in liquid sodium silicate. The utilization of industrial dissipate materials such as GGBS, fly ash, and waste glass powder was used as the binding ingredients, and stone crusher dust was used as fine aggregates. The experimental investigation showed that a quality concrete can be easily produced using alkali activation of industrial wastes satisfying its strength requirements. The statistical models developed shown that there is a significant relationship between various cube and cylinder strengths. Thus alkali-activated concrete(AAC) can effectively reduce the environmental hazards associated with OPC concrete, which also provides an effective way of utilizing major industrial byproducts

Suitability of Scoria as Fine Aggregate and Its Effect on the Properties of Concrete

The increase in the demand for concrete production for the development of infrastructures in developing countries like Ethiopia leads to the depletion of virgin aggregates and high cement demand, which imposes negative environmental impacts. In sustainable development, there is a need for construction materials to focus on the economy, efficient energy utilization, and environmental protections. One of the strategies in green concrete production is the use of locally available construction materials. Scoria is widely available around the central towns of Ethiopia, especially around the rift valley regions where huge construction activities are taking place. The aim of this paper is therefore to analyze the suitability of scoria as a fine aggregate for concrete production and its effect on the properties of concrete. A differing ratio of scoria was considered as a partial replacement of fine aggregate with river sand after analyzing its engineering properties, and its effect on the mechanical properties of concrete were examined. The test results on the engineering properties of scoria revealed that the material is suitable to be used as a fine aggregate in concrete production. The replacement of scoria with river sand also enhanced the mechanical strength of the concrete. Generally, the findings of the experimental study showed that scoria could replace river sand by up to 50% for conventional concrete production.

RESPONSE SURFACES FOR PROPERTIES OF CONCRETE WITH CLAY BRICK POWDER AS SUBSTITUTE FOR CEMENT

This study examined the application of pulverize clay brick wastes as alternative constituent for Portland cement replacement in green concrete production using the response surface methodology (RSM). The adopted response surface approach is central composite design (CCD). The statistical models were developed between the concrete constituents (clay brick powder and water cement ratio) and their response variables (slump, compressive and split tensile strength). Relationships were established and mathematical models in terms of actual factors from predicted responses were developed. The influence of the considered factors on the properties of response were visually observed from the contour and response surface plots. The statistical models of experimental values clearly depict that the obtained experimental values are in close agreement with the predicted values, which validates the response surface models with desirability value of 1. The results show that pulverized clay brick waste have significant influence on the properties of concrete than the water cement (w/c) ratio, however, a declining trend was seen for all analyzed concrete properties. In addition, this study showed that the pulverized waste brick can be used as alternative substitute for Portland cement up to 20% in the production of sustainable concrete.

Durability performance of a novel ultra-high-performance PET green concrete (UHPPGC)

The production of green sustainable concrete with enhanced performance against severe environmental conditions by using recycle waste materials has been a primary concern for recent studies. This article reports a study on investigating the effect of incorporating ultra-fine palm oil fuel ash (UPOFA) with shredded recycled waste bottle in form of Polyethylene Terephthalate (PET) on the engineering and transport properties of ultra-high-performance concrete. UPOFA was used as a partial replacement binder in varied proportions (20% and 40%) of the total cement binder, whereas shredded recycled PET bottles were added as reinforced fibre by 1% of the total mix volume. The greatest compressive strength was registered by a combination of 20% UPOFA and PET fibre in U20-UHPPGC. The combination of 40% UPOFA and PET fibres in U40-UHPPGC mix demonstrated a superior enhancement in terms of transport properties at the age of 28 days, such as porosity, initial surface absorption, gas permeability, water permeability and rapid chloride permeability. Thus, pozzolanic UPOFA can improve the engineering and transport properties of ultra-high-strength concrete. The overall results indicated that the PET fibre reinforced with UPOFA can produce UHPPGC with promising improvements in engineering and transport properties. The incorporation of waste materials into concrete constructions can reduce cement consumption and prevent the environmental pollution with save energy at the same time.

Recycling of Waste Limestone as Fine Aggregate for Conventional and Green Concretes

This paper presents the results of the experimental works to investigate the use of waste limestone from water treatment industry as fine aggregate in green concrete. Two concrete mixtures with a constant water-to-binder ratio of 0.3 were prepared for this investigation, in which, the normal concrete mixture was designed following the guidelines of ACI 211 standard, while the green concrete mixture was designed using densified mixture design algorithm (DMDA) technology. For comparison, both types of concrete samples were subjected to the same test program, including fresh properties, compressive strength, strength efficiency of cement, drying shrinkage, electrical surface resistivity, ultrasonic pulse velocity, and thermal conductivity. Test results indicate that both concrete mixtures showed the excellent workability due to the round-shape of waste limestone aggregate and the use of superplasticizer. In addition, the green concrete mixture exhibited a better performance in terms of engineering properties and durability in comparison with the normal concrete mixture. The results of the present study further support the recycling and reuse of waste limestone as fine aggregate in the production of green concrete.

Strength and transport properties of concrete composites incorporating waste carpet fibres and palm oil fuel ash

The use of industrial wastes in the production of green and sustainable concrete has attracted much attention in recent years because of the low-cost of waste materials along with saving a significant place for landfill purposes and also enhance the performance of concrete. In this study, the strength and transport properties of concretes comprising waste carpet fibre and palm oil fuel ash (POFA) were investigated. The VeBe time and slump tests on fresh concrete in addition to compressive strength, tensile strength, flexural strength, sorptivity, and chloride penetration of hardened concrete were tested. The combined effect of carpet fibres and POFA was investigated using microstructural analysis in terms of scanning electron microscopy (SEM) and X-Ray Diffraction (XRD). Six concrete mixes containing 0–1.25% fibres with a length of 20 mm were cast for ordinary Portland cement (OPC). Further, six concrete batches with the same fibre content were made, where 20% POFA substituted OPC. The incorporation of waste carpet fibres and POFA decreased the workability of concrete. The inclusion of carpet fibres to both OPC and POFA mixtures reduced the compressive strength values. The positive interaction amongst carpet fibre and POFA lead to greater splitting tensile and flexural strengths. Also, sorptivity and chloride penetration of the OPC and POFA-based mixtures were significantly decreased by the inclusion of carpet fibre up to 0.75%. The influence of POFA on the transport properties of concrete composites was noticed to be more considerable along with the curing periods.

Utilization of construction and agricultural waste in Malaysia for development of Green Concrete: A Review

Green Concrete (GC) is defined as a concrete that utilize a waste material for at least one of its component. The production of GC has been increasing due to the drawback of conventional concrete that create many environmental problems. In Malaysia, the amount of waste generates from agricultural and construction industries were increasing every year. Hence, one of the solutions to reduce the impact of conventional concrete and limited landfill spaces due to excessive waste is by utilizing it in concrete. This paper reviews the possible use of construction waste (Recycle Concrete Aggregate) and agricultural waste (Palm Oil Fuel Ash, Rice Husk Ash and Palm Oil Fibre) as partial replacement for the basic material in a concrete to produce an innovative Green Concrete. The optimum replacement level for each type of waste was also been review. Green Concrete also has the potential to reduce environmental pollution and solve the depletion of natural sources. The result from this review shows that the addition of agricultural waste or construction waste in concrete indicate positive and satisfactory strength when compared to normal concrete. Finally, a mass production of Green Concrete can fulfil the Construction Industry Transformation Plan (CITP) 2016-2020 made by CIDB that emphasizes on a construction system which is environmentally sustainable.

RETRACTED: Microstructure and residual properties of green concrete composites incorporating waste carpet fibers and palm oil fuel ash at elevated temperatures

With the increasing amount of waste generation from different processes, there has been a growing interest in the use of waste in producing sustainable building materials to achieve potential benefits. This study investigated the influence of waste polypropylene carpet fibers and palm oil fuel ash (POFA) on the microstructure and residual properties of concrete composites exposed to elevated temperatures. Four mixes containing carpet fibers (0% and 0.5%) and POFA (0% and 20%) were prepared. The specimens were exposed to high temperatures (200, 400, 600 and 800 °C) for 1 h. The fire resistance of the concrete specimens was then measured in terms of mass loss as well as both residual ultrasonic pulse velocity (UPV) and compressive strength. The role of carpet fibers and POFA was investigated through the analysis of the microstructure in terms of scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The results revealed that the addition of waste polypropylene carpet fibers to the concrete matrix significantly enhanced the fire resistance and residual compressive strength in addition to eliminating the explosive spalling behavior of the concrete composites at elevated temperatures. The fire resistance of the concrete mixtures was further enhanced by the inclusion of POFA. The study revealed that the utilization of waste carpet fiber and palm oil fuel ash in the production of sustainable green concrete is feasible both technically and environmentally.

RETRACTED: Durability performance of green concrete composites containing waste carpet fibers and palm oil fuel ash

Cleaner production is a pressing concern of the 21st century. Waste materials resulting from different industrial processes requires proper management to ensure a cleaner environment. The use of recycled materials in new green concrete production is very attractive due to the low-cost related to the waste materials in addition to saving required space for landfill purposes and the development as well as improvement in the concrete properties. This paper focuses on the durability properties of green concrete composite, which comprised of waste polypropylene (PP) carpet fiber and palm oil fuel ash (POFA). Properties studied include slump and VeBe time of fresh concrete as well as water absorption, sorptivity, chloride penetration, carbonation, and drying shrinkage of hardened concrete. Carpet fiber of 20 mm in length and six volume fractions of 0–1.25% were used with ordinary Portland cement (OPC). Another six concrete mixes were cast whereby OPC was replaced by 20% POFA. It was observed that the combination of PP carpet fiber and POFA decreased the slump values and increased the VeBe time of the fresh concrete mixes. In addition, water absorption, sorptivity, chloride penetration, and carbonation depth of the concrete composite for both OPC and POFA content mixtures were reduced with the addition of carpet fiber, with volume fractions of up to 0.75%. The positive interaction between carpet fibers and POFA subsequently led to the lower drying shrinkage of the concrete composite. The influences of POFA on the durability performance of concrete was observed to be more significant at longer curing periods. The findings of the study demonstrated that there is a promising future for the use of waste carpet fibers as a fibrous material in the production of a green and durable concrete. Green concrete also minimizes solid wastes, improves air quality, and leads to sustainable cement and concrete industry.

Green concrete production incorporating waste carpet fiber and palm oil fuel ash

With the increasing amount of waste generation from various processes, there has been a growing interest in the utilization of waste in producing building materials to achieve potential benefits. This paper highlights the results of an experimental investigation on the performance of concrete incorporating waste carpet fiber (WCF) and palm oil fuel ash (POFA) as partial replacements of ordinary Portland cement (OPC). Six volume fractions varying from 0 to 1.25% of 20-mm-long carpet fiber were used with OPC concrete mixes. Another six mixes were made that replaced OPC with 20% POFA. The specimens were cured in water and tested for fresh and hardened state properties. The combination of WCF and POFA decreased the slump values and increased the VeBe time of fresh concrete. The addition of WCF to either OPC or POFA concrete mixes did not improve the compressive strength or modulus of elasticity. At 91 days, the compressive strength was in the range of 38.1–49.1 MPa. The positive interaction between WCF and POFA, however, leads to high tensile and flexural strengths, thereby increasing the concrete ductility with higher energy absorption and improved crack distribution. The maximum increases in tensile and flexural strengths compared to those of plain concrete were achieved by the addition of 0.5% carpet fiber at the age of 91 days. The ultrasonic pulse velocity (UPV) was examined and was classified as good quality concrete. The study showed that the use of waste carpet fiber and palm oil fuel ash in the production of sustainable green concrete is feasible both technically and environmentally.

Green concrete production with ceramic wastes and laterite

Laterite is a dominant soil material in Nigeria but its use in structural concrete has not been overly explored. In this study, ceramic wastes obtained from construction and demolition activities and laterite were used as replacement for natural aggregates. Workability and strength characteristics of the concrete and microstructure of selected samples were obtained. Results showed that natural aggregate concrete was more workable than the laterised concrete. Both the compressive strength and splitting tensile strength increased with curing age, however, laterised concrete with 10% laterite content and 75% ceramic coarse aggregate yielded higher strength at 28days than the reference concrete.

RECYCLING LOCAL INDUSTRIAL WASTES FOR PRODUCTION OF GREEN CONSTRUCTION MATERIALS

Industrial waste is one of the most important sources of environmental pollution in the world and Egypt. Providing economic opportunities for recycling these wastes represent an essential solution to this problem to encourage waste producers to dispose it safely and to provide an added value for these wastes. This research work will study the feasibility of recycling certain industrial wastes for production low-cost building materials and improving the soil compaction characteristics. In this research work, the efficiency of recycling some common local industrial wastes in production of construction materials was explored. The selected wastes include cement kiln dust (i.e. bypass) and ceramics powder. Previous researches and the chemical analysis showed that both wastes are promising as cement replacement materials. However, this exploratory phase is an initial investigation targeting the chemical properties of theses wastes for efficient use of both wastes to replace cement –partially- in mortar and plain concrete elements as well as bricks. The advantage of replacing part of the cement content with waste materials has double environmental action, by which reducing cement use leading to less carbon dioxide emission in addition to the safe recycling of the industrial wastes. Based on the selected condition of the cement bypass and ceramic powder, no significant enhancement was recorded in the mortar and concrete mixes had various ratios of cement replacement. However, the main physical and mechanical properties of some of the tested mixes provided promising values for using these mixes for production of more green plain concrete, mortar and bricks. For the soil enhancement application, addition of cement bypass to soil -commonly found in delta region- increased the California Bearing Ratio (CBR) value of this soil by 300%. Currently more comprehensive investigation is running to cover more than cement and ceramic factories in order to have a reliable data base of the properties of these types of industrial wastes and the efficient recycling of these wastes in construction materials and soil improvement applications.

Green High Performance Concrete Based on Sustainable Development

Green high performance concrete is concrete materials which can reduce the load of the earth's environment, coordinate development with the ecosystem and create comfortable living environment. The relationship between the construction materials and the sustainable development and the characteristic of green high performance concrete were introduced, the measures of green concrete production was analyzed and the work essential for the development of green high performance concrete was proposed in this paper. The research shows that the development of green high performance concrete is the inevitable way for the sustainable development of concrete.