Improvement In Durability Properties Research Articles

Induction furnace slag as fine and coarse aggregate in quaternary blended self-compacting concrete: A comprehensive study on durability and performance

This research explores the innovative use of Induction Furnace slag Aggregate (IF-slag) as both fine and coarse aggregates in Quaternary Blended Self-Compacting Concrete (QBSCC) mixes, an area that has received limited attention in previous studies. The primary aim is to compare the durability characteristics of QBSCC mixes containing natural aggregate versus those incorporating IF-slag aggregate. A total of 18 SCC mixes were prepared in two groups: one using natural aggregate and the other using IF-slag aggregate. Each group consisted of eight optimized QBSCC mixes alongside a reference SCC mix. The QBSCC mixes were formulated using Ordinary Portland Cement (OPC) with Supplementary Cementitious Materials (SCM) such as Silica Fume (SF), Class F-Fly Ash (FAF), and Ground Granulated Blast Furnace Slag (GGBFS). Previous work by the authors analysed the fresh and mechanical properties of these QBSCC mixes. This study assesses various durability properties, including water absorption, permeable pore volume, absorption coefficient sorptivity, ultrasonic pulse velocity, resistance to chloride ion penetration, electrical resistivity, and thermal conductivity. Experimental findings indicate that SCC prepared with IF-slag exhibited inferior durability performance compared to natural aggregate. However, regardless of aggregate type, QBSCC mixes outperformed the SCC mix containing 100% OPC. Notably, the SCC-47.5 (OPC)/52.5(SCM) QBSCC mix demonstrated significant improvements in durability properties, achieving a reduction of 25% in water absorption, 24% in permeable pore volume, 48% in absorption coefficient, and 46% in sorptivity. QBSCC mixes also exhibited resistance to chloride ion penetration and enhanced electrical resistivity. Moreover, using quaternary blends reduced the thermal conductivity and improved the energy efficiency.

Durability properties of steel, polyamide, and polyethylene fiber-reinforced geopolymer mortar made with recycled concrete aggregate and glass powder as fillers

This research produced steel, polyamide, and polyethylene fiber-reinforced metakaolin-red mud-based geopolymer mortar with recycled concrete aggregate (RCA) and waste glass powder (GP) as fillers. To study the durability behavior, a series of experiments were conducted to investigate the resistance of manufactured geopolymer mortar against high temperatures (300 °C, 600 °C, and 900 °C), freeze-thaw (180 cycles), and sulfate attacks (10% sodium sulfate and 10% magnesium sulfate solution). According to the findings, using GP as a filler material by replacing RCA 50% produced the best strength results. Moreover, adding fibers to the mixture showed significant improvement in durability properties. Steel fiber-reinforced mixtures showed better resistance against high temperatures and freeze-thaw cycles than the rest of the series. Steel fibers improved the flexural strength to 15.58% at 300 °C, 19.26% at 600 °C, and 42.94% at 900 °C compared to the control mixture. Against sulfate attack, fiber-reinforced mixtures behaved better than non-fibrous control mixtures. Weight loss was observed after high-temperature exposure, while the increased weight of samples was observed after exposure to freeze-thaw cycles and sulfate attack. SEM analysis observed a weak interfacial transition zone between the matrix and the fibers.

Performance evaluation of polyurethane-nano silica modified cement mortar

Cement mortar is known to be effective in taking compression than tension. The tensile strength of cement mortar is a cause of concern when it comes to unreinforced applications. The present study aims at performance evaluation of Polyurethane (PU) and Nano silica blended cement mortar. Various proportion of polyurethane (0.5%, 1%, 2%) modified with nano silica (5%, 10% by weight of PU) is blended to the mix during specimen preparation. The water-cement ratio is maintained at 0.35 and the superplasticizer dosage maintained at 0.2% weight of cement. The performance study such as compressive strength, split tensile strength, resistance to thermal exposure, abrasion resistance was done. The relative assessment was also done with cement mortars incorporating silica fume (5% by weight of cement). Compared to cement and silica fume incorporated mortar, the mixes modified with PU-nano silica shows enhancement in split tensile strength. PU-nano silica composite also shows improvement in durability properties. XRD characterization was also performed on the composite mortar to identify the compounds present.

The Influence of Crystalline Admixtures on the Properties and Microstructure of Mortar Containing By-Products

Crystalline admixtures and industrial by-products can be used in cement-based materials in order to improve their mechanical properties. The research examined long-term curing and the exposure to environmental actions of polymer–cement mortars with crystalline admixture (CA) and different by-products, including Bengħisa fly ash and Globigerina limestone waste filler. The by-products were introduced as a percentage replacement of the cement. A crystallization additive was also added to the mixtures in order to monitor the improvement in durability properties. The mechanical properties of the mortar were assessed, with 20% replacement of cement with fly ash resulting in the highest compressive strength after 540 days. The performance was analyzed with respect to various properties including permeable porosity, capillary suction, rapid chloride ion penetration and chloride migration coefficient. It was noted that the addition of fly ash and crystalline admixture significantly reduced the chloride ion penetration into the structure of the polymer cement mortar, resulting in improved durability. A microstructure investigation was conducted on the samples through Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Crystals forming through the crystalline admixture in the porous structure of the material were clearly observed, contributing to the improved properties of the cement-based polymer mortar.

Effects of nano-TiO2, nano-Al2O3, and nano-Fe2O3 on rheology, mechanical and durability properties of self-consolidating concrete (SCC): An experimental study

The objective of this study is to assess and compare the effects of different nanoparticles, namely nano-TiO2, nano-Al2O3 and nano-Fe2O3, on the performance of self-consolidating concrete (SCC) in terms of fresh, mechanical, and durability properties through performing different experiments. TiO2, Al2O3, and Fe2O3 nanoparticles with the average diameter of 18, 15, and 14 nm were used with two different contents of 3% and 5% by weight of cement. For assessing the fresh properties of SCC, slump flow, V-funnel, L-box, and column segregation tests were conducted. For the mechanical properties, compressive strength of concrete was investigated, and for the durability properties rapid chloride migration (RCM), electrical resistivity, rapid chloride penetration (RCP), and water penetration depth tests were carried out. The result showed that the workability properties of the mixes slightly improved by 3% addition of nanoparticles while increasing this value to 5% decreased the workability. For higher content of nanoparticles, the incorporation of nanoparticles in the mixes increased the water demand and consequently caused a reduction of workability.For compressive strength, nano-Fe2O3 showed a superior effect on the enhancement of strength in comparison to nano-Al2O3 and nano-TiO2. This observation was attributed to the formation of calcium ferric hydrate (C-F-H) gel in the microstructure. Moreover, the addition of all the nanoparticles resulted in an improvement of durability properties. High surface area of nanoparticles provided nucleation sites for cement particles and expedited the hydration process development. The formation of a higher content of hydration products helped the densification of microstructure. Moreover, nanoparticles controled the growth pattern of C-S-H gel, which led to the formation of a homogenous microstructure with smaller pore sizes and consequently to lower permeability against penetration of aggressive ions i.e., chloride. It is concluded that partial replacement of cement with nanoparticles on average improved the compressive strength and durability properties of SCC, but resulted in a reduction of workability.

Mechanical and Durability Properties of Fly Ash and GGBS Based Fiber Reinforced Concrete

Concrete is one of the most commonly and widely adopted material for construction. Cement is used as primary binder material to produce Concrete. However, every tonne of Cement production releases one tonne of greenhouse gases which results in global warming; due to continuous and ever increased usage of Cement and natural sand are causing uncontrollable global warming and depletion of natural resources respectively year by year. This tendency needs to be retarded if not arrested, by developing a comprehensive approach to use more and more pozzolanic mineral admixtures and manufactured sand (M-Sand) in Concrete. In this study on fiber reinforced concrete (with steel fiber @ 1% of binder), Ordinary Portland Cement (OPC) is replaced up to 50% with Fly Ash and Ground Granulated Blast-Furnace slag (GGBS) for M30 grade of Concrete. Mechanical properties like compressive strength and split tensile strength at 7 days and 28day age are tested. Additionally, durability tests like water absorption and sorptivity tests are conducted after 28days of curing. The test results indicated that workability was increased and there was no significant improvement in durability properties on increasing the percentage of OPC replacement. However, 30% of OPC replacement is found to be optimum for strength criteria

Effect of Micro Polypropylene Fibre on the Performance of Fly Ash-Based Geopolymer Concrete

Abstract Geopolymer offers significant promise to the construction world as a possible alternative to ordinary Portland cement (OPC). Like conventional Portland cement concrete, the matrix brittleness in geopolymer composites can be reduced by introducing suitable fibre reinforcement. A few investigations on fibre reinforced geopolymer composites are available. However there is still a gap to comprehend and enhance their performance. This paper describes the effect of incorporating micro polypropylene fibres on the strength and durability characteristics of geopolymer concrete. The engineering and durability properties like workability, compressive strength, split tensile strength, flexural strength, modulus of elasticity, and sorptivity of geopolymer concrete reinforced with micro polypropylene fibres is presented. The effect of the sulfuric acid attack on Geopolymer Concrete reinforced with micro polypropylene fibres is also discussed. The results show that hydrophobic characteristics of the micro polypropylene fibre led to weak contact with the geopolymer binder and hence weakened the mechanical performance of the fly ash based geopolymer matrix. However significant improvements in durability properties were noted.

Potential Use of Calcined Kaolinite-Based Wastes as Cement Replacements in Concrete – An Overview

The use of supplementary cementitious material (SCM) to partially replace cement is a promising strategy to reduce CO2 emission and improve the overall sustainability of construction industry. Recent studies revealed that calcined clay could be used as a pozzolanic material and demonstrated an improvement in durability properties of concrete. The pozzolanic reactivity of calcined clay mainly depends on the kaolinite content due to its disordered crystal structure. They can use to replace cement at considerably high level (∼30%), and even higher (∼50%) if addition limestone powder is used. Since kaolinite is the key source of pozzolanic activity, reusing kaolinite-based waste materials could be a promising and sustainable approach instead of exploiting natural clay for calcined clay cement. This paper summarises recent published works on the use of calcined kaolinite waste as partial cement substitutions in concrete, including thermally activated coal gangue and pre-calcined clay brick and ceramic wastes which have been burnt in their fabrication process. The properties of concrete using these kaolinite-based waste materials are also discussed.

Sustainability on durability of self compacting concrete from C&D waste by improving porosity and hydrated compounds: A microstructural investigation

This research article is on establishment of sustainability with reference to the durability properties of self compacted recycled aggregate concrete (SCRAC) by improving porosity and hydrated compounds in concrete. Partial replacement of fly ash by silica fume and virgin concrete aggregate (VCA) by recycled concrete aggregate (RCA) are taken for preparing the SCRAC by adopting suitable mix design method along with proposed two stage mixing approach (TSMAsfc). This two stage mixing approach makes significant improvement in durability properties as the slurry of cement and silica fume fills the pores and cracks and makes interfacial transition zones (ITZs) stronger. Microstructure analysis using the electron probe micro analyser (EPMA) is carried out to justify the reason of improvement of durability properties of SCRAC. Image analysis of backscattered secondary electron (BSE) images are carried out for the quantitative analysis of different compounds (C-S-H, UH, CH and pores) at the ITZ. Image analysis and EPMA analysis confirmed that the ITZ gets stronger by adopting two stage mixing approaches.

Role of Ground Glass Fiber as a Pozzolan in Portland Cement Concrete

Millions of tons of fiberglass are produced annually for a variety of applications. Because of stringent quality requirements and operational characteristics of the manufacturing plants, a significant quantity of fiberglass that does not meet required specifications of the industry ends up as waste in landfills. This study investigated the use of ground glass fiber (GGF) that had been discarded by plants because it did not meet prescribed standards, as a supplementary cementitious material (SCM) for portland cement. Three replacement levels (10%, 20%, and 30% by mass) for portland cement in paste, mortar, and concrete mixtures were studied. Mechanical and durability properties of the mixtures were compared with two control mixtures: a mixture made up of 100% portland cement and a mixture with 25% Class F fly ash as a cement replacement material. It was observed in these studies that even though replacement of portland cement with GGF did not lead to any significant changes in the mechanical behavior of hardened concrete, there were significant improvements in durability properties at replacement levels up to as high as 20%. The use of GGF was found to improve significantly the resistance of mortar mixtures to alkali–silica reaction and sulfate attack. In addition, the use of GGF as an SCM significantly reduced the chloride ion permeability of concrete. Results of this study show that using GGF as an SCM can result in a better durability performance compared with a mixture with a similar level of Class F fly ash.

Influence of grinding method and particle size distribution on the properties of Portland-limestone cements

The benefits of using limestone as a partial replacement of Portland cement (PC) are well established in the literature. Economic and environmental advantages by reducing CO2 emissions are well known. This paper describes the influence of the producing method (intergrinding or separate grinding) and particle size distribution on properties of Portland-limestone cements (PLC). Experiments were carried out on cement paste including normal consistency, time of setting, and heat of hydration, on cement mortar including compressive and flexural strength, and potential alkali reactivity of aggregates, and on concrete including compressive strength, sorptivity, electrical resistivity, and rapid chloride permeability. In this study, ten types of cements including two types of PC, and eight types of PLC were used. The results show that mechanical and durability properties of PLC were not affected significantly by grinding method. In addition, the use of cements with high fineness is not very effective on improvement of durability properties.

Effect of mixture proportions on the drying shrinkage and permeation properties of high strength concrete containing class F fly ash

Sustainability of concrete can be improved by using large volume of fly ash as a replacement of cement and by ensuring enhanced durability of concrete. Durability of concrete containing large volume of class F fly ash is dependent on the design of mixture proportions. This paper presents an experimental study on the effect of mixture proportions on the drying shrinkage and permeation properties of high strength concrete containing large volume of local class F fly ash. Concrete mixtures were designed with and without adjustments in the water to binder ratio (w/b) and the total binder content to take into account the incorporation of fly ash up to 40% of total binder. Concretes, in which the mixture proportions were adjusted for fly ash inclusion achieved equivalent strength of the control concrete and showed enhanced properties of drying shrinkage, sorptivity, water permeability and chloride penetration as compared to the control concrete. The improvement of durability properties was less significant when no adjustments were made to the w/b ratio and total binder content. The results show the necessity of the adjustments in mixture proportions of concrete to achieve improved durability properties when using class F fly ash as a cement replacement.

Durability of mortar and concretes containing slag with low hydraulic activity

Granulated blast furnace slag has been widely used as a partial substitute for Portland cement in many applications because of advantages which include cost reduction, reduction in heat evolution and improvement of durability properties. However, the effectiveness of slag depends on its hydraulic reactivity. In this paper, the results of an experimental study on the effect of slag with low hydraulicity on the mechanical and durability properties of concrete and the performance of mortar under sulfate attack are discussed. Special attention is given to gas permeability and water absorption of slag concrete. The durability of slag concrete is improved at long term at low Water/Binder ratio. Sulfate resistance of mortar is improved by slag replacement up to 30%.