The performance and mechanical properties of geopolymer concrete

Publisher AIP Conference Proceedings, American Institute of Physics Inc.

DOI https://doi.org/10.1063/5.0236590

Country Iraq

Location Kufa

Alternative cement technologies are gaining popularity as a result of the cement industry’s increasing concerns about the environment. Current research suggests improved environmental and durability performance cannot be achieved without new binders. geopolymer concrete (GPC) uses fly ash (FA) instead of conventional Portland cement. The purpose of this study is to examine the influence of FA: Ground granulated blast-furnace slag (GGBS) by employing FA based-GPC compared to cement concrete on the compressive strength, splitting strength, modulus of rapture, density, and water absorption of concrete. The varied ratio of FA 30%, metakaolin 70%, FA 30% and GGBS 70% for GPC was utilized in this investigation. The outcomes obtained show that the GPC made of FA 30% and GGBS 70% gives higher compressive strength than that of cement concrete at 7, and 28 days. The porosity and water absorption of GPC were lower than that of cement concrete and the percentage of decrease was 1% for geopolymer containing GGBS as a binder. These results can be modified further when using other materials with treated GGBS, FA, and MK, in different ratios.

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Enhancement properties of fly ash-based geopolymer concrete using dune sand and glass fiber

Publisher AIP Conference Proceedings, American Institute of Physics Inc.

DOI https://doi.org/10.1063/5.0238284

Country Iraq

Location Kufa

This paper investigates the enhancement of properties Geopolymer concrete based on fly ash utilizing dune sand as a fine aggregate and incorporating glass fiber. The utilization of fly ash and dune sand addresses sustainability and environmental concerns, while the addition of glass fiber aims to improve mechanical properties. The study includes experimental testing to evaluate compressive strength, flexural strength, splitting tensile strength, density, and water absorption of Geopolymer concrete specimens. The results demonstrate that the incorporation of glass fiber and 25% dune sand positively influences the strength of geopolymer concrete. The geopolymer concrete with glass fiber and 25% dune sand recorded the maximum splitting, flexural, and compressive tensile strengths over all curing ages, offering a promising approach to enhance the performance of sustainable concrete materials.

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Mapping vegetation cover changes in Kirkuk governorate using remote sensing and GIS techniques

Publisher AIP Conference Proceedings, American Institute of Physics Inc.

DOI https://doi.org/10.1063/5.0212579

Country Iraq

Location Kufa

This research examined the assessment of changes in land cover, particularly vegetation changes. The study was applied to a specific area, the Al-Rashad district in Kirkuk governorate, northeastern Iraq. It searched for the changes in plant cover areas using the spectral signature of crops and supervised classification. To evaluate the vegetation and land cover in the study area, a comparison was made using different datasets with periods 2015, 2018, and 2021. Besides, a spectral signature was used to specify the type of crops obtained from (the Ministry of Science and Technology Department of Space and Communications). A supervised classification approach (Support Vector Machine SVM), was applied for land cover classifications. The land cover variation rates were derived from the Sentinel2 images of the years (2015, 2018, and 2021). The vegetation classes were based on the spectral-spatial analyses of three crops (wheat, barley, and corn). Each crop area had been calculated in each season for three years in the study area. Based on study findings, it was discovered that the vegetation cover had been increased extremely. Vegetation cover area increased 26% and became 322.81 km2 in 2021. Besides, the area of each crop was calculated where Barley and corn have increased in 2021 to become 146.943km2 and 114.351 km2 respectively, while Wheat decreased to become 61.515 km2. Moreover, classification overall accuracy was equal to 85%, 95%, and 85% for 2015, 2018, and 2021 respectively, with kappa coefficient of 0.76, 0.90, and 0.80 respectively.

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Effect of nano pam oil fuel ash and nano eggshell powder on concrete durability

Publisher AIP Conference Proceedings, American Institute of Physics Inc.

DOI https://doi.org/10.1063/5.0195328

Country Malaysia

Location Langkawi

In this investigation, the efficiency of eggshell powder (ESP) and palm oil fuel ash (POFA) was assessed as alternative materials to replace ordinary Portland cement (OPC) at different replacement levels. Combining ESP and POFA in nanoparticle size led to the form of a high-pozzolanic reaction during concrete production. The resistance of the pozzolanic concrete towards chemical attack was examined. The quantity of waste materials used as partial cement replacement influences the resistance of concrete against chemical attack. The deterioration of concrete containing both nano eggshell powder and nano palm oil fuel ash increases as the immersion time become longer. Future research is proposed to further explore the kinetic reaction upon inclusion of nano eggshell and nano palm oil fuel ash as partial cement replacement in cementitious environment.

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Using And Optimizing The Recycled Aggregates In Concrete: A Review

Publisher AIP Conference Proceedings, American Institute of Physics Inc.

DOI https://doi.org/10.1063/5.0171434

Country Iraq

Location Nineveh

Reusing aggregate from building and demolition waste can help protect the ordinary natural aggregate supply, reduce landfill demand, and drive toward a more sustainable environment. This paper examines the recycled history of recycled aggregate and recycled aggregate. A general review of how recycled aggregates were used by previous researchers in recent years and their findings are reviewed in this review paper. In addition, methods for enhancing the mechanical characteristics of recycled aggregate and long-term efficiency such as improving the properties without modifying the recycled aggregate (namely, different concrete mixing designs and the addition of reinforcing fibers) were reviewed. The machine learning model for predicting compressive strength in addition to compressive stress modulus and graphs for recycled aggregate concrete are reviewed, as well as their limitations are discussed. It discusses the research perspectives of recycled aggregate, namely the development of “green” processing methods for recycled aggregate and additional guidance on building a database to predict the strength of recycled aggregate.

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Properties of rubberized cement mortar containing silica fume

Publisher AIP Conference Proceedings, American Institute of Physics Inc.

DOI https://doi.org/10.1063/5.0105414

Country Iraq

Location Baghdad

Currently, increased production of various goods and supplies such as car tires led to an excessive amount of worn tires making disposal a major issue as waste rubber derived from tires are not easily degraded or decomposed therefore many research has been undertaken to use these materials in engineering purposes to reduce their negative environmental impacts such as cement mortar to reduce its adverse environmental influences. this study shows the possibility of using crumb rubber in mortar by partially replacing (5%,9%,13%,17%,21%,25%, and 29%) of fine aggregate by volume, with silica fume included as partial substitution (15%) of cement weight to see their influence on cement mortar properties and comparing their performances with the controlled specimens having no crumb rubber such as water absorption, unit weight, shrinkage, compressive strength, flexural strength and splitting tensile strength with varying rubber replacement levels. The results obtained from the study were that compressive strength, flexural strength, and splitting tensile strength reduce when increasing the rubber content in mortar. In conversely, the incorporation of silica fume into the composite, on the other hand, enhanced the mechanical properties of the mortars and moderated the rate of strength drop. When the substitute fraction was increased, water absorption increased. When the percentage of replacement in mortar cement rises, the density decreases. Also, as the amount of rubber rises, shrinkage decreases.

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An overview of Mechanical and Thermal Properties of Nano Concrete

Publisher AIP Conference Proceedings, American Institute of Physics Inc.

DOI https://doi.org/10.1063/5.0094450

Country Iraq

Location Samawah

In This article the nanomaterial effect on concrete was discussed. Nowadays, nanotechnology has received wide attention to enhance conventional concrete properties. In contrast, the topic of this research is to find thermal insulation and related material with good mechanical properties, so nanomaterial was added to concrete mixtures to take advantage of the nanoparticle’s enhanced properties on concrete and mortar in terms of thermal insulation. In latest research, researchers have been carried out to boost the portability of concrete on thermal insulation by manufacturing lightweight concrete. As it is known to have low compressive strength, considering that the density reduction of concrete is one of the thermal insulation methods. The researchers find that using nanomaterial is a good topic in improving concrete’s mechanical and thermal properties by reviewing previous research. Also, it affirms the necessity of continuing scientific efforts to study various factors affecting nanomaterial use in concrete. The present article aims to review research that has used nanomaterials to improve the mechanical and thermal properties of concrete, identify the positive and negative aspects of using nanomaterials in concrete, and define future directions for nanotechnology in building and construction technology globally. Also includes the most important design and operational variables influencing the use of nanotechnology in concrete to reach a reliable reliability of nonconcrete technology.

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Physicochemical properties of modified epoxy used for reinforcing concrete by carbon fiber reinforced polymer

Publisher IOP Conference Series: Materials Science and Engineering

DOI https://iopscience.iop.org/article/10.1088/1757-899X/1058/1/012054

Country Iraq

Location Erbil

This work is an experimental investigation about the properties of sand-powder adhesive subjected to high temperature. Thus, three main mixtures were tested. These mixes contain three different sand to adhesive ratios; 0:1, 1:1 and 1.5:1. The Simultaneous of Thermal Analyzers (STA); represent real-time measurement, change of sample weight analysis and heat flow were investigated. The results indicated that the physicochemical properties (residual mechanical properties, residual weight, weight losing rate, glass transition temperature (Tg), Carbonate point or extrapolated onset temperature (To), and heat flow) have been remarkably enhanced by the addition of sand-powder. The addition of sand resulted in increased epoxy resistance to high heat. When the sand-powder exposed to 550 ° C, the weight loss of the epoxy was 52%, 30% and 25% for sand to adhesive ratios equal to 0, 1, and 1.5 % respectively. In other words, the epoxy containing a high proportion of sand retained 25% of its weight under the influence of a high temperature degree. Adding sand increases the temperature and time necessary to reach the first and second carbonation point. Adding sand to adhesive increase the temperature needed to reach the glazing point Tg and the point of reversal in the curve derived from loss of weight.

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Reinforced Concrete Slabs Containing Recycled Concrete as Coarse Aggregate

Country IRAQ

Location Duhok

This research presents an experimental study on the performance of reinforced recycled aggregate concrete (RAC) that contains one of two types of recycled coarse aggregate, one from normal concrete and another from self – compacting concrete (SCC). The replacement percentages (by weight) of natural coarse aggregate with the recycled coarse aggregate are (0, 33.3, 66.7 & 100) % by weight. Moreover, Silica Fume was used as an admixture for all (RAC) mixtures. Concrete compressive strength, split tensile strength, and flexural strengths were studied for all of the reference and (RAC) mixtures at (28) days age, by testing concrete cubes, cylinders and reinforced concrete slabs specimens respectively. The results showed that the using of recycled waste concrete as concrete as aggregate will largely decreasing the slabs flexure strength while using of recycled (SCC) mixtures have relatively small effect in reducing the slabs flexure strength. The adding of silica fume to the concrete mix will increasing the slabs flexural strength and that increase is larger for recycled (SCC) aggregate mixtures than the recycled concrete aggregate mixtures. The results also indicate that the compressive strength and tensile strength are decreased by different ratio when using of recycled waste concrete as aggregate, while using of recycled (SCC) aggregate will also reduce the tensile strength and the modulus of rupture while the compressive strength increased when using this type of recycled aggregate. On the other hand, the mixtures with the Silica Fume showed a significant enhancement in the mechanical properties compared to those without the Silica Fume.

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Improve Recycled Concrete Aggregate properties in Order to Use It in Paving Application as Aggregate

Publisher IOP Publishing Ltd

DOI https://iopscience.iop.org/article/10.1088/1757-899X/1075/1/012033

Country Malaysia

Location Malaysia

The amount of crushed cement concrete continues to increase daily as a result of the demolition of old structures, thereby increasing pollution. To cope with the pressure imposed by the rise in environmental awareness and the stringent disposal regulations set by environmental protection agencies, effective measures for handling and disposing of crushed concrete must be implemented. Instead of simply disposing of crushed concrete, alternative efforts should be considered to utilize it as a recyclable material. The objective of this study was to improve recycled concrete aggregate (RCA) to be able to using it in paving application. Three types of treatments applied to improve RCA properties. In this study three types of treatment were used to improve RCA properties. Theses treatment are soak RCA in HCL acid for 24 hours, grind RCA in Los Angeles Abrasion machine, re-grind RCA particle in jaw crush machine. In order to evaluate each treatment the aggregate properties are determined. All properties were determined for RCA passing and retained sieve size of 5 mm and 1.18 mm respectively. The calculated properties are bulk specific gravity of aggregate, absorption value, abrasion value of aggregate and angularity number of RCA. The most important conclusions are Soaking RCA in HCL acid has side effect on the specific gravity of aggregate, Putting RCA in Los Angeles Abrasion machine make RCA particles more rounded. Finally, crush RCA in jaw crusher machine for second is best way to improve RCA properties.

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Different configurations of cores and shear walls in tall buildings

Publisher IOP Conference Series: Earth and Environmental Science

DOI https://iopscience.iop.org/article/10.1088/1755-1315/357/1/012005

Country Iraq

Location Malaysia

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