Sensor-Assisted Assessment of the Tribological Behavior Patterns of AA7075 Hybrid MMC Reinforced with Multi-Wall Carbon Nanotubes and Pulverized Fuel Ash

In recent years, the deployment of sensors and other ancillary technologies has turned out to be vital in the investigation of tribological behavioral patterns of composites. The tribological behavioral patterns of AA7075 hybrid metal matrix composites (MMCs) reinforced with multi-wall carbon nanotubes (MWCNTs), and pulverized fuel ash (PFA) were investigated in this work. The stir casting technique was used to fabricate the composites. The mechanical properties such as tensile strength and hardness were determined for the fabricated material. Besides, microstructure analysis was performed for these AA7075 hybrid MMCs reinforced with MWCNTs and pulverized fuel ash. A pin-on-disc wear testing setup was used to evaluate the wear rate, in which the EN 31 steel disc was used as the counter-face. Taguchi’s design of the experiments was used to optimize the input parameters that impact the characteristics of the hybrid composites, and ANOVA (analysis of variance) was used to determine the contribution of input parameters on the wear behavior. Electrical discharge machining (EDM) was conducted on the AA7075 hybrid metal matrix composites using a copper electrode for determining the material removal rate. These investigations and the results were utilized for determining the optimized output process parameter values of the AA7075 metal matrix composite.

Effects of ground granulated blast furnace slag and pulverized fuel ash on rheology of concrete

The rheology of concrete containing Pulverized Fuel Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS) has been scarcely studied and reported, despite their increase application as Supplementary Cementitious Materials (SCM) that drives improvement of sustainability of the construction industry. This work studied the effect of these SCMs and Superplasticizer proportions on rheological properties of concrete using rate controlled concrete rheometer. Two groups of mixes containing replacement or addition on mass basis using either PFA or GGBS or their combinations were derived from the control mix. The dynamic yield stress, plastic viscosity and 28 day compressive strength of the control mix are 1258 Pa, 6 PaS, and 40.5 MPa respectively. The results of the rheology tests of the various binary mixes (PFA and Portland cement) and ternary mixes (Portland cement, PFA and GGBS) structural concrete shows wide disparity in the measured rheological parameters. The results show that the decrease in dynamic yield stress of the ternary mix containing 20% GGBS is 4.1%, whereas the decrease in dynamic stress of the ternary mix containing 20% PFA is 35.9% compared to the control ternary mix. The high volume Portland cement replaced ternary concrete can therefore be effectively characterized as a workable and pumpable concrete. Keywords: Rheology, PFA, GGBS, superplasticizer, concrete.

Comparison of Effect of Colloid Graphite Nano Particle on Properties of Fuel Ash-Green Cement Composite

Aims: This current study aims at comparing the effect of colloid graphite nano particle on the properties of class C pulverized fuel ash-green cement composite (CPFA-GCC). Background: In view of major and minor oxides, the CPFA is a very valuable artificial pozzolanic material, which is generated by power plant that uses high-calorie charcoal in the manufacturing of electrical energy, for the cement industry. The CPFA is light-brown color and includes more than 10 Objective: The purpose of study reported in this article compares new properties of the CPFA-CC modified by either the GNP or the CGNP to discuss assessment of effect difference between the GNP and the CGNP. It also concludes the effectiveness of GNP and colloid GNP on the development of optical atomic absorbance spectra, stiffness-time, and flow, apparent density, apparent porosity, and apparent fullness as well as early age compressive stress. Method: The effect of colloid graphite nano particle on properties of fuel ash-green cement composite was measured as standard tests method and literature analysis accepted Result: Characteristic result of the GNP and the CGNP provides the defining of certain effect as the stiffness accelerator, the apparent density, and the apparent fullness increaser, the flow and the apparent porosity reducer as well as compressive stress gainer for green cement based composite at early age. Conclusion: In view of positive characteristic of the GNP and of the CGNP, those could be used such engineering applications as the green construction building, the infrastructure renewal, the construction retrofit, and the construction reinforcement for dramatically extend service life, that has taken advantage of the maintenance cost. Other: As explained in this article, the CGNP is the most logical, productive and sustainable additive to be used in manufacturing of the class C pulverized fuel ash-green cement binder and composite for saving the future of pure cement, making infrastructure safer, extending service life, reducing maintenance cost and natural resource use.

A Review on Green Concrete Using Low-Calcium Pond Ash as Supplementary Cementitious Material

Nowadays, the construction cost is very high with the use of crucial material such as cement, fine aggregate and coarse aggregate. This study includes the use of Pulverized fuel ash waste materials as partial replacement of cement and fine aggregate. Industries in India produce a large amount of waste such as fly ash, Bottom ash, Pond ash, etc., that can be useful in the partial replacement of all raw materials due to their different properties. Therefore, we study the number of useful research documents in this field and try to improve with locally available waste material can be proven economical as well. The objective of this study was to determine the environmental impacts of open dumping of pond ash around a thermal power plant.

DURABILITY PROPERTIES OF TERNARY BLENDED FLOWABLE HIGH PERFORMANCE CONCRETE CONTAINING GROUND GRANULATED BLAST FURNACE SLAG AND PULVERIZED FUEL ASH

The use of ordinary Portland cement as the primary binder in concrete production resulted in the high carbon footprint of the concrete material which cause a great deal of environmental impacts over the years. The consumption of OPC is especially significant for high strength concrete, which require a very high cement content (more than 450 kg/m3). Hence, supplementary cementitious materials such as ground granulated blast furnace slag (GGBS) and pulverized fuel ash (PFA) were chosen as partial replacement materials of OPC for concrete production in the research due to their ease of availability from the steelmaking manufacturing sectors and coal-fired electricity power stations in the country. As the sustainability of concrete is also our main concern, the durability performance of flowable high performance concrete containing high volume of GGBS and PFA (50-80% replacement of OPC) has been studied in this research. Therefore, the durability properties of flowable high performance concrete had been assessed in term of air permeability, porosity, water absorption and capillary action. From the results of assessment, all ternary blended concrete mixes exhibited better durability performances than control OPC concrete at later ages due to formation of denser microstructure by pozzolanic reaction of GGBS and PFA. It is concluded that the mix proportion of flowable high performance concrete production with 60% replacement of OPC by GGBS and PFA has the optimum durability performances than OPC concrete.

An experimental study on cyclic behaviour of reinforced concrete connections using waste materials as cement partial replacement

A series of cyclic tests on unconfined beam–column connections with composite concrete materials are conducted. Cement is partially replaced by waste materials using two different percentages of 15% and 20%. The proper percentage of cement replacement is found to be 15% for the pulverized fuel ash, silica fume, and iron filings. Increasing the percentage to 20% tends to relatively decrease concrete compressive strength, weaken the joint, and reduce its ductility. It is recommended using pulverized fuel ash to enhance the performance of beam–column connections under cyclic loading. Silica fume and iron filings have also enhanced the joint response, but the enhancement is most remarkable when using 15% pulverized fuel ash. The implementation of composite concrete has increased the joint’s ductility and reduced its level of damage based on the type and percentage of the implemented waste material. Furthermore, the disposal of waste materials into the concrete mix is a good solution for reducing environmental pollution.

Mechanical properties and flexural behaviour of fibrous cementitious composites containing hybrid, kenaf and barchip fibres in cyclic exposure

In this study, the mechanical properties and flexural behaviour of the fibrous cementitious composites containing hybrid, kenaf and barchip fibres cured in cyclic exposure were investigated. Waste or by-product materials such as pulverized fuel ash (PFA) and ground granulated blast-furnace slag (GGBS) were used as a binder or supplementary cementitious to replace cement. Barchip and kenaf fibre were added to enhance the mechanical properties and flexural behaviour of the composites. A seven mix design of the composites containing hybrid, kenaf and barchip fibre mortar were fabricated with PFA-GGBS at 50% with hybridization of barchip and kenaf fibre between 0.5% and 2.0% by total volume weight. The composites were fabricated using 50 × 50 × 50 mm, 40 × 40 × 160 mm and 350 × 125 × 30 mm steel mould. The flexural behaviour and mechanical performance of the PFA-GGBS mortar specimens were assessed in terms of load-deflection response, load compressive response, and crack development, compressive and flexural strength after cyclic exposure for 28 days. The results showed that specimen HBK 1 (0.5% kenaf fibre and 2.0% barchip fibre) and HBK 2 (1.0% kenaf fibre and 1.5% barchip fibre) possessed good mechanical performance and flexural behaviour. As conclusion, the effect of fibres was proven to enhance the characteristics of concrete or mortar by reducing shrinkage, micro crack and additional C-S-H gel precipitated from the pozzolanic reaction acted to fill pores of the cement paste matrix and cement paste aggregate interface zone between mortar matrix and fibre bonding.

Simplex-Lattice Hydration Prediction and Microstructure Verification of Cementitious Systems

In this investigation, the age-dependent hydration development of blended pastes containing Portland cement (PC), pulverized fuel ash (PFA) and silica fume (SF) was assessed by quantifying the amount of CH and non-evaporable water using thermo-gravimetric analysis (TGA). Microstructure was investigated using scanning electron microscope (SEM). It was observed that the amount of liberated CH increases up to three-days in PC-PFA binary blended pastes, after which it progressively decreases and this reduction was proportional to the PFA dosage. The introduction of SF to PC-PFA binary mixtures to form ternary blended pastes has caused an early reduction of CH at one day where the majority of SF has been consumed during the first seven-days. The incorporation of 10% SF to PC-PFA pastes altered the low rate of hydration at early age. In addition, the presence of PFA showed insignificant influence on the non-evaporable water content until three-days then its effect became significant after seven-days. On the other hand, SF increased the non-evaporable water content from early ages up to seven-days. However, beyond 28 days, the presence of SF did not exhibit further pozzolanic activity. Furthermore, the ternary blended systems significantly increased the non-evaporable water content within three to seven days compared to the reference paste. Moreover, prediction nonlinear models of these hydration parameters were developed using the simplex-lattice design and validated against the experimental results. The latter have been further supported with SEM microstructural analysis showing good agreement between the predicted and realistic hydration.