Modelling Compression Strength of Waste PET and SCM Blended Cementitious Grout Using Hybrid of LSSVM Models

Abstract

Nowadays, concretes blended with pozzolanic additives such as fly ash (FA), silica fume (SF), slag, etc., are often used in construction practices. The utilization of pozzolanic additives and industrial by-products in concrete and grouting materials has an important role in reducing the Portland cement usage, the CO2 emissions, and disposal issues. Thus, the goal of the present work is to estimate the compressive strength (CS) of polyethylene terephthalate (PET) and two supplementary cementitious materials (SCMs), namely FA and SF, blended cementitious grouts to produce green mix. For this purpose, five hybrid least-square support vector machine (LSSVM) models were constructed using swarm intelligence algorithms, including particle swarm optimization, grey wolf optimizer, salp swarm algorithm, Harris hawks optimization, and slime mold algorithm. To construct and validate the developed hybrid models, a sum of 156 samples were generated in the lab with varying percentages of PET and SCM. To estimate the CS, five influencing parameters, namely PET, SCM, FLOW, 1-day CS (CS1D), and 7-day CS (CS7D), were considered. The performance of the developed models was assessed in terms of multiple performance indices. Based on the results, the proposed LSSVM-PSO (a hybrid model of LSSVM and particle swarm optimization) was determined to be the best performing model with R2 = 0.9708, RMSE = 0.0424, and total score = 40 in the validation phase. The results of sensitivity analysis demonstrate that all the input parameters substantially impact the 28-day CS (CS28D) of cementitious grouts. Among them, the CS7D has the most significant effect. From the experimental results, it can be deduced that PET/SCM has no detrimental impact on CS28D of cementitious grouts, making PET a viable alternative for generating sustainable and green concrete. In addition, the proposed LSSVM-PSO model can be utilized as a novel alternative for estimating the CS of cementitious grouts, which will aid engineers during the design phase of civil engineering projects.

Development of an Epoxy-Based Rapid Tool with Low Vulcanization Energy Consumption Channels for Liquid Silicone Rubber Injection Molding

“…In this study, a sustainable LSR injection mold with both conformal heating and conformal cooling channels was demonstrated. This injection mold was a green mold [ 26 ] and met sustainable development goals [ 27 ]. Therefore, the findings of this study are very practical and provide the greatest application potential in the design stage of an LSR injection mold.…”

Enhancing Surface Temperature Uniformity in a Liquid Silicone Rubber Injection Mold with Conformal Heating Channels

“…The process parameters of FFF included a printing speed of 30 mm/s, bed temperature of 60 • C, printing temperature of 200 • C, and layer thickness of 0.1 mm. The molding material was ELASTOSIL ® LR 3003/50 US A/B (Wacker Chemical AG Inc., Munich, Germany) [22] because it is suitable for manufacturing an optical convex lens through LSR injection molding. The primary purpose of numerical simulation was to understand the temperature uniformity of conventional heating channels in the LSR molds.…”

“…To eliminate the air bubbles, the mixture was put into a vacuum pump (F-600, Feiling Inc. New Taipei City, Taiwan). Both the conventional and conformal heating channels were fabricated with polyvinyl butyral (PVB) filament feedstock (Thunder 3D Inc., New Taipei City, Taiwan) [19,20] using fused filament modeling (FFF) technology [21,22] (Teklink smart solution Inc., New Taipei City, Taiwan). The process parameters of FFF included a printing speed of 30 mm/s, bed temperature of 60 °C, printing temperature of 200 °C, and layer thickness of 0.1 mm.…”

A Probability-based Fuzzy Multi-objective Optimization for Material Selection

“…Most of them solve the problems by simple combination of the fuzzy concept with traditional multiobjective optimization approaches, such as the "TOPSIS (Technique for Order Preference by Similarity to Ideal Solution)", "AHP (Analytic Hierarchy Process)", "VIKOR (VIsekriterijumsko KOmpromisno Rangiranje)", "MOORA (Multi-Objective Optimization on basis of Ratio Analysis)", etc. [1][2][3][4][5][6][7][8][9][10][11][12]. However, this kind of hybrid cannot be seen as reasonable approaches because of the existences of inherent shortcoming in the traditional multi-objective optimization approaches due to their "normalization" and "additive algorithm" for various objectives [6][7][8][9][10][11][12][13][14][15].…”