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

Tensile behaviour of reinforced UHPFRC elements under serviceability conditions

[EN] Tension stiffening is an essential effect that influences the behaviour of concrete structures under serviceability conditions, mainly regarding crack control and deflection behaviour. Serviceability conditions can be studied experimentally by running the so-called uniaxial tensile test. This paper reports an extensive experimental research conducted to study the tensile behaviour of reinforced Ultra-High Performance Fibre-Reinforced Concrete (R-UHPFRC) under service conditions by uniaxial tensile testing. The parameters studied were the reinforcement ratio and the steel fibre content in a experimental programme including 36 specimens. Special testing equipment and methodology to measure the post-cracking deformation of R-UHPFRC ties were developed, and special attention was paid to the shrinkage effect. The tensile elements' axial stiffness was approximately parallel to the bare bar response after microcracking formation showing a full tension-stiffening response. The average tensile capacity of the reinforced elements (tension stiffening response) was achieved. Concrete's contribution in the R-UHPFRC ties with the tensile properties deriving from four-point bending tests (4PBTs) on non-reinforced UHPFRC specimens was also compared. The experimental results revealed a slight increase in concrete's contribution with the higher reinforcement ratio. Moreover, the concrete's contribution in the tensile elements was higher than the characteristic tensile properties deriving from 4PBTs.This study forms part of Project BIA2016-78460-C3-1-R, supported by the Ministry of Economy and Competitiveness of Spain.Khorami, M.; Navarro-Gregori, J.; Serna Ros, P. (2021). Tensile behaviour of reinforced UHPFRC elements under serviceability conditions. 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Green driver: Travel behaviors revisited on fuel saving and less emission

Road transportation is the main energy consumer and major contributor of ever-increasing hazardous emissions. Transportation professionals have raised the idea of applying the green concept in various areas of transportation, including green highways, green vehicles and transit-oriented designs, to tackle the negative impact of road transportation. This research generated a new dimension called the green driver to remediate urgently the existing driving assessment models that have intensified emissions and energy consumption. In this regard, this study aimed to establish the green driver's behaviors related to fuel saving and emission reduction. The study has two phases. Phase one involves investigating the driving behaviors influencing fuel saving and emission reduction through a systematic literature review and content analysis, which identified twenty-one variables classified into four clusters. These clusters included the following: (i) FEf1, which is driving style; (ii) FEf2, which is driving behavior associated with vehicle transmission; (iii) FEf3, which is driving behavior associated with road design and traffic rules; and (iv) FEf4, which is driving behavior associated with vehicle operational characteristics. The second phase involves validating phase one findings by applying the Grounded Group Decision Making (GGDM) method. The results of GGDM have established seventeen green driving behaviors. The study conducted the Green Value (GV) analysis for each green behavior on fuel saving and emission reduction. The study found that aggressive driving (GV = 0.16) interferes with the association between fuel consumption, emission and driver's personalities. The research concludes that driver's personalities (including physical, psychological and psychosocial characteristics) have to be integrated for advanced in-vehicle driver assistance system and particularly, for green driving accreditation

Genotyping and phylogenetic analysis of hydatid cysts isolated from livestock in Bushehr province, Iran

Hydatid cyst is one of the parasitic zoonoses caused by infection with the larval stage of Echinococcus granulosus tapeworm. The spread of this parasite is global and is of great importance in terms of public health. To date, ten different species of this parasite have been identified that differ in characteristics such as life cycle, epidemiology and pathogenesis. The purpose of this study was to determine the genotype and phylogenetic relationship of hydatid cysts isolated from livestock of Bushehr province, Iran. About 62 samples of hepatic and pulmonary hydatid cysts were collected from slaughtered animals. DNA extracted by phenol–chloroform method was amplified by PCR using primers specific for the cox1 gene. The PCR products of 50 samples were sequenced and analyzed using BioEdit software and compared with sequences in the GenBank. The phylogenetic tree was drawn using Neighbor Joining tree-NJ method, and its reliability was evaluated. Sequencing results showed that out of 50 sequenced samples, 43 samples had the genotype of Echinococcus granulosus and 7 samples had the genotype of Taenia hydatigena. By drawing a phylogenetic tree, all 43 hydatid cyst samples belonged to G1 strain. The predominance of G1 strain of hydatid cyst in livestock of Bushehr province shows the main role of this genotype in establishing the life cycle of parasite in this region and if the genotype of the parasite in dogs and humans is determined, then these findings can be used to disrupt the life cycle of the parasite and reduce the human infections

Behaviour of strengthened timber beams using near surface mounted Basalt Fibre Reinforced Polymer (BFRP) rebars

Reinforcement of structural timber members with fibre reinforced polymer (FRP) rods offers merits over that of the conventional steel type. In recent times, near surface mounted (NSM) FRP reinforcement with timber has emerged as a promising alternative for reinforcing timber structures in both flexural and shear loading configurations. Previous investigations have shown that NSM FRP reinforcement technique has higher bond performance than externally bonded equivalents because it (NSM FRP technique) is able to utilise the full capacity of the FRP materials. In spite of these merits, the investigations and the use of this innovative technique are limited. In this paper, an experiment was conducted to investigate the bond characteristics and performance of NSM basalt FRP reinforcement with solid timber structures. In order to predict the performance of the reinforced beam structures, unreinforced control timber members of the same timber characteristics were tested. The results showed that the average bond capacity of the NSM FRP reinforced members was 16% higher than the corresponding unreinforced beams

A sustainable historic waterfront revitalization decision support tool for attracting tourists

Waterfront revitalization would be an effective strategy to preserve heritages, conserve the contaminated or abandoned site and inspire the identity and authenticity. However, there is no decision support tool to quantify and evaluate the sustainability accreditation of waterfronts in tourism attraction. This research aimed to identify the most potential waterfront typology in tourism attraction and develop the waterfront sustainable revitalization (SWR) index assessment model. The SWR index can assist policy makers and urban developers to analyze the heritage waterfronts using Analytical Hierarchy Process (AHP) method. The research found out the historic waterfront has the highest potential in tourism attraction among other typologies. And, pollution moderator is mostly important sub-criterion in tourism absorption (WC2.2 = 0.1294); followed by Identity (WC1.2 = 0.1272) and Safety and well-being (WC1.3 = 0.1043). The SWR index can be applied in any waterfronts in heritage cities around the world, while this research implemented it as a case study in Bandar Maharani, Muar, Malaysia. It resulted Bandar Maharani was ranked as grade C; means, usable waterfront to which extent environmental, social and physical revitalization are needed. The SWR index can be coupled with other decision-making methods in future, to reduce its inconsistencies and increasing accuracy

Thermal and mechanical properties of hemp fabric-reinforced nanoclay-cement nano-composites

The influence of nanoclay on thermal and mechanical properties of hemp fabric-reinforced cement composite is presented in this paper. Results indicate that these properties are improved as a result of nanoclay addition. An optimum replacement of ordinary Portland cement with 1 wt% nanoclay is observed through improved thermal stability, reduced porosity and water absorption as well as increased density, flexural strength, fracture toughness and impact strength of hemp fabric-reinforced nanocomposite. The microstructural analyses indicate that the nanoclay behaves not only as a filler to improve the microstructure but also as an activator to promote the pozzolanic reaction and thus improve the adhesion between hemp fabric and nanomatrix

Influence of single and binary doping of strontium and lithium on in vivo biological properties of bioactive glass scaffolds

Effects of strontium and lithium ion doping on the biological properties of bioactive glass (BAG) porous scaffolds have been checked in vitro and in vivo. BAG scaffolds were prepared by conventional glass melting route and subsequently, scaffolds were produced by evaporation of fugitive pore formers. After thorough physico-chemical and in vitro cell characterization, scaffolds were used for pre-clinical study. Soft and hard tissue formation in a rabbit femoral defect model after 2 and 4 months, were assessed using different tools. Histological observations showed excellent osseous tissue formation in Sr and Li + Sr scaffolds and moderate bone regeneration in Li scaffolds. Fluorochrome labeling studies showed wide regions of new bone formation in Sr and Li + Sr doped samples as compared to Li doped samples. SEM revealed abundant collagenous network and minimal or no interfacial gap between bone and implant in Sr and Li + Sr doped samples compared to Li doped samples. Micro CT of Li + Sr samples showed highest degree of peripheral cancellous tissue formation on periphery and cortical tissues inside implanted samples and vascularity among four compositions. Our findings suggest that addition of Sr and/or Li alters physico-chemical properties of BAG and promotes early stage in vivo osseointegration and bone remodeling that may offer new insight in bone tissue engineering