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Background Saprolegniasis often cause a significant economic losses to fish hatchery and intensive fish industry. The treatment of saprolegnoid diseases with malachite green seems to have harmful effect and is considered as a mutagenic and carcinogenic substance. The teratogenic and carcinogenic potential of malachite green increased the necessity to find an effective alternative treatment to control the disease. Methods In the present study, seven fungicides used in agriculture were investigated to control Saprolegnia parasitica and S. diclina in vitro. The antifungal activity of each fungicide was compared with that of malachite green as reference fungicide using food poisoning technique. Fish toxicity of the effective fungicides was performed to detect the most applicable fungicides in fish aquarium. Results Four of seven fungicides were found to be effective against the two saprolegnoid fungi. Azoxystrobin and metalaxyl were the most effective fungicides inhibited fungal growth of the two saprolegnoid fungi completely at concentration of 200 ppm and 250 ppm respectively while cyazofamid and etridiazole were moderately effective. Acute toxicity assay of the two effective fungicides showed metalaxyl was low toxic to fish with LC50 of 360 ppm while azoxystrobin was 225 ppm. Hence, it was confirmed that 200 and 250 ppm of azoxystrobin and metalaxyl which completely inhibited mycelial growth of the saprolegniod fungi could be safely used for saprolegniasis control. Conclusion These fungicides which proved to be effective and fishery safer may be applicable as a aquatic fungicides avoiding teratogenic and carcinogenic risk of malachite green.

Bars made of fiber reinforcement polymer (FRP) are in common usage for concrete reinforcing instead of steel reinforcing since steel could be affected by corrosion. The concrete beams reinforced by FRP bars have been studied mostly in longitudinal direction without shear reinforcement. The primary objective of this investigation was to design and advance an algorithm for selection procedure of the parameters influence on prediction of shear resistance of reinforced concrete beams by FRP. Six input parameters were used which represent geometric and mechanical properties of the bars as well as shear features. These parameters are: web width, tensile reinforcement depth, ratio of shear and depth, concrete compressive strength, ratio of FRP reinforcement, FRP modulus of elasticity and beam shear resistance. The searching algorithm is based on combination of artificial neural network and fuzzy logic principle or adaptive neuro fuzzy inference system (ANFIS). Based on the obtained results ratio of shear and depth has the strongest influence on the prediction of shear resistance of reinforced concrete beams by FRP. Moreover, combination of tensile reinforcement depth and ratio of shear and depth is the most influential combination of two parameters on the prediction of shear resistance of reinforced concrete beams by FRP. Finally, combination of tensile reinforcement depth, ratio of shear and depth and FRP modulus of elasticity is the most influential combination of three parameters on the prediction of shear resistance of reinforced concrete beams by FRP.

The effectiveness and performance of beam to column connections have been highly affected by the type and properties of structures. An effective and stable design of beam to column connections is critical because in many cases, a single connection must be able to carry several types of loads at the same time. When designing these connections, it is important to consider erection, serviceability, strength, and cost-effectiveness as an efficient design that must be economic in practice. In this study, experimental results for the designed beam to column connection in concrete frames have been applied while evaluating the outcomes. Development and applying of Extreme Learning Machine (ELM) for moment prediction of beam to column connections are the objectives of this study. By understanding and integrating the relevant simulation outcomes and other statistical indicators, the reliability of the computational models has been analyzed.

Significant growth in the consumption of plastic products is observed all over the world in recent years; this has contributed to increasing the production of plastic waste. Reuse of plastic waste in the production of concrete or mortar appears as an environmentally friendly solution for getting rid of plastic waste, due to its ecological and economic advantages. Furthermore, it leads to a decrease in plastic waste incineration or the proportion of plastic waste in landfills. Several studies presented the properties of cementitious composites (mortar and concrete) containing different types of plastic waste as aggregate (PWA). This review paper summarizes the previous studies until 2019, discussing the use of recycled plastic aggregate as fine aggregate in cementitious composites and its impact on physical, mechanical properties and durability. To present a comprehensive review, a total of 103 studies were discussed. This paper begins by illustrating the types of plastics and recycled plastics and plastics recycling process. Followed by a discussion of the PWA influence on cementitious composites properties in three sections; physical properties, mechanical properties and durability respectively. Furthermore, thermal conductivity and fire behaviour are discussed in a separate section. In addition to relationships between concrete properties. Many recommendations for future studies are provided. Significant growth in the consumption of plastic products is observed all over the world in recent years; this has contributed to increasing the production of plastic waste. Reuse of plastic waste in the production of concrete or mortar appears as an environmentally friendly solution for getting rid of plastic waste, due to its ecological and economic advantages. Furthermore, it leads to a decrease in plastic waste incineration or the proportion of plastic waste in landfills. Several studies presented the properties of cementitious composites (mortar and concrete) containing different types of plastic waste as aggregate (PWA). This review paper summarizes the previous studies until 2019, discussing the use of recycled plastic aggregate as fine aggregate in cementitious composites and its impact on physical, mechanical properties and durability. To present a comprehensive review, a total of 103 studies were discussed. This paper begins by illustrating the types of plastics and recycled plastics and plastics recycling process. Followed by a discussion of the PWA influence on cementitious composites properties in three sections; physical properties, mechanical properties and durability respectively. Furthermore, thermal conductivity and fire behaviour are discussed in a separate section. In addition to relationships between concrete properties. Many recommendations for future studies are provided.

The punitive environmental legislation set by the global community has shifted the direction of research involve in construction industry towards the utilization of secondary raw materials in designing and constructing new structures. Rice husk (RH) is a by-product obtained from the rice mill process whose generation accounts up to 200 kg per ton of rice. The existing literature showed the vast potential of using rice husk ash (RHA) as a replacement for cement or as admixtures. This paper aims to critically review previous studies on RHA as a waste material. The utilization of this waste in concrete contributes to nurturing more sustainable and greener development, thereby lessen carbon footprints and minimize solid waste disposal issues. A state-of-the-art-review of literature on the use of RHA is presented in this paper. The impact of RHA on the properties of concrete such as workability, density, compressive strength, flexural strength, splitting tensile strength, modulus of elasticity, durability properties as well as its impact on sustainability are compiled. In addition, the technical results are complimented with the microstructural analysis evaluated through scanning electron microscopy (SEM). From the data garnered, it is postulated that RHA beneficially enhance the mechanical strengths coupled with improvement of resistant to sulfate and acid attack. This paper advances novel recommendations and directions for future research towards the application of green RHA-based construction products. The punitive environmental legislation set by the global community has shifted the direction of research involve in construction industry towards the utilization of secondary raw materials in designing and constructing new structures. Rice husk (RH) is a by-product obtained from the rice mill process whose generation accounts up to 200 kg per ton of rice. The existing literature showed the vast potential of using rice husk ash (RHA) as a replacement for cement or as admixtures. This paper aims to critically review previous studies on RHA as a waste material. The utilization of this waste in concrete contributes to nurturing more sustainable and greener development, thereby lessen carbon footprints and minimize solid waste disposal issues. A state-of-the-art-review of literature on the use of RHA is presented in this paper. The impact of RHA on the properties of concrete such as workability, density, compressive strength, flexural strength, splitting tensile strength, modulus of elasticity, durability properties as well as its impact on sustainability are compiled. In addition, the technical results are complimented with the microstructural analysis evaluated through scanning electron microscopy (SEM). From the data garnered, it is postulated that RHA beneficially enhance the mechanical strengths coupled with improvement of resistant to sulfate and acid attack. This paper advances novel recommendations and directions for future research towards the application of green RHA-based construction products.

An experimental investigation was conducted to determine the effect of internal curing of natural lightweight aggregates (LWAs) on the shrinkage, mechanical properties, and durability of high-performance concrete (HPC). Conventional aggregates were partially substituted with prewetted coarse and fine LWA at dosages of 5, 10, and 20% by volume. The early age autogenous shrinkage and drying shrinkage of the HPC mixtures were monitored for up to 180 days. The investigated properties of the HPC mixtures included compressive strength, modulus of elasticity, and splitting tensile strength at 28 days, as well as rapid chloride permeability and water absorption. The results revealed that, at a replacement level of 20% for both coarse and fine aggregates, the reduction in autogenous shrinkage of the HPC mixtures was approximately 118% at 28 days and 65% at 18 days. Furthermore, the test results indicated that the autogenous shrinkage measured between 15 h and 7 days after casting was reduced by approximately 75%. Fine LWAs were more effective in reducing autogenous shrinkage than coarse LWAs. This was attributed to the small particles, which allowed a good distribution of the water-filled internal curing within the cement matrix. It was also found that using up to 20% LWA could modify the 28-day autogenous shrinkage of HPC by reducing the cube compressive strength up to 70 MPa as compared to 86 MPa for the control mixture. In addition, the obtained strength values of the concrete mixes were found to be within the acceptable range specified by the ACI standard to be categorized as HPC. The findings of the study revealed that the utilization of LWA is feasible as an internal curing method for decreasing the volume changes, particularly at the early ages, and for avoiding the formation of cracks in HPC.

During the entire service life of pavement, the exposed surface must have an adequate level of roughness, so as to expedite the friction amongst vehicle wheels and the surface of the pavement. Therefore, the abrasion and skid resistance should be considered when measuring the wear, sliding, and skidding levels of a pavement surface. It is well-known that the lower the skid resistance value, the higher the percentage of traffic accidents (particularly under wet conditions). Therefore, this study aimed to enhance the abrasion and skid resistance of concrete as a pavement material by reinforcement with polypropylene (PP) fibers. The influences of waste PP fibers and palm oil fuel ash (POFA) on the tensile and compressive strengths, modulus of elasticity, abrasion resistance (tested using a Bohme surface abrasion machine), and skid resistance (tested using a British pendulum skid resistance tester) of the concrete were investigated. Overall, 12 mixes were cast, including six concrete mixtures comprising 0%, 0.25%, 0.5%, 0.75%, 1%, and 1.25% PP fibers with 100% ordinary Portland cement (OPC). Another six concrete mixtures were prepared with the same fiber dosages, but with 20% POFA as a cement replacement. The experimental results revealed that using PP fibers at concentrations up to 1.25% reduced the compressive strength of concrete mixtures by approximately 17%. However, the addition of PP fibers significantly enhanced the tensile strength (by 30%), along with the abrasion and skid resistance of all of the fiber-reinforced concrete mixtures. It was found that the 1.25% PP fiber mix had the highest abrasion and skid resistance, i.e., approximately 25% higher than that of a control mix. In addition, the POFA mixes performed better than the OPC mixes, owing to the high pozzolanic activity and the formation of additional hydration products.

This study experimentally investigated the effectiveness of the inclusion of basalt fibers in concrete to enhance the performance of the concrete components when exposed to elevated temperatures. Concrete specimens were reinforced with basalt fibers at dosages of 0.25%, 0.5%, 0.75%, and 1%, and then exposed to high temperatures of up to 600 °C. Chopped basalt fibers act as fillers and bridge the gaps and micro-cracks within concrete, resulting in the high strength and energy absorption capacity of basalt fiber-reinforced concrete. At elevated temperatures, when the surface-bound water becomes evaporated, additional stress was found to be released through the softening of basalt fibers. Moreover, at such high temperatures, basalt fibers held the aggregates and cement paste in position by gripping the macro-cracks when the hydration products of concrete began to decompose. The residual strength in fiber-reinforced concrete was thereby significantly higher than that in non-fibered concrete. However, beyond the optimum level of fiber addition, agglomeration, and the non-uniform dispersion of fibers was observed, which results in the lowered performance of the concrete.

This study investigated the effect of corroded web reinforcement on the shear behavior of reinforced concrete (RC) beams. In this study, nine shear-critical RC beams were cast and tested. Six of these beams were corroded stirrups, while the remaining three beams were uncorroded stirrups serving as control samples. An accelerated corrosion technique was employed to corrode the stirrups in the beams. After the accelerated corrosion process, the beams were tested in three-point bending over a simply supported span. The shear span-to-depth ratio was kept constant at 3 for all beam specimens. The effects of the corrosion level, the type of steel stirrups (smooth or deformed), and the stirrup diameter were considered in the tests. The corrosion damage could easily be observed in the form of rust stains and corrosion cracks, which developed parallel to the stirrups. The beams with higher corrosion levels showed a reduction in their shear capacities. This reduction was more apparent in the beams with deformed steel stirrups. The shear capacities of the test beams were analyzed using a theoretical model that considers the effects of corrosion of the stirrups. The results of the analysis showed a good correlation between the experimental and theoretical shear strengths of the beam specimens.

This research investigates the possibility of grinding and burning bivalve clam seashells to produce seashell ash powder. This ash is used to partially replace cement by 5, 10, 15 and 20% by weight. These mixes are tested and compared with a SC0 that has 0% seashell ash powder (SC0). The fresh and hardened properties of all mixes are studied through a variety of tests, including: slump, unit weight, compressive strength and splitting tensile strength. The durability of seashell concrete cubic specimens is studied by immersion in 5% NaOH(aq) and MgSO4(aq) solutions. The addition of thermally treated seashells increased the calcium hydroxide content. The results also show that the compressive strength of the 5% replacement is slightly higher than the SC0 at 28 and 90 days of age, while the tensile strength is higher than the standard for the 5% and 10% of replacement at 7 and 28 days. Furthermore, the slump test value generally increases with increasing the percentage of replacement. The highest durability against sulfate and alkaline attacks is obtained with 5% replacement of cement with seashells which reported the lowest decrease in weight and the highest compressive strength after immersion in 5% NaOH(aq) and MgSO4(aq) solutions. The 5% replacement mix is the optimum percentage of replacement. Therefore, this study recommends replacing cement with 5% seashell cement. This research investigates the possibility of grinding and burning bivalve clam seashells to produce seashell ash powder. This ash is used to partially replace cement by 5, 10, 15 and 20% by weight. These mixes are tested and compared with a SC0 that has 0% seashell ash powder (SC0). The fresh and hardened properties of all mixes are studied through a variety of tests, including: slump, unit weight, compressive strength and splitting tensile strength. The durability of seashell concrete cubic specimens is studied by immersion in 5% NaOH(aq) and MgSO4(aq) solutions. The addition of thermally treated seashells increased the calcium hydroxide content. The results also show that the compressive strength of the 5% replacement is slightly higher than the SC0 at 28 and 90 days of age, while the tensile strength is higher than the standard for the 5% and 10% of replacement at 7 and 28 days. Furthermore, the slump test value generally increases with increasing the percentage of replacement. The highest durability against sulfate and alkaline attacks is obtained with 5% replacement of cement with seashells which reported the lowest decrease in weight and the highest compressive strength after immersion in 5% NaOH(aq) and MgSO4(aq) solutions. The 5% replacement mix is the optimum percentage of replacement. Therefore, this study recommends replacing cement with 5% seashell cement.

Proficient and proper management of different types of waste materials is one of the major concerns to ensure a clean environment. The utilization of wastes in the production of concrete has attracted much attention in recent years because of the low-cost of waste materials along with saving a significant place for landfill purposes and also enhance the performance of concrete. In this study, the possibility of sheep wool fibers (SWF) and modified sheep wool fibers (MSWF) in the production of fiber-reinforced concrete was investigated by assessing the mechanical and microstructural properties. Eight concrete mixes containing 0–6% normal wool sheep fibers with a length of 70 mm were made. Further, four concrete mixes with the modified wool sheep fibers of 0–1.5% with the same length were made. The addition of both SWF and MSWF reduced the slump values of fresh concrete. The inclusion of sheep wool fibers to concrete mixes decreased the compressive strength. However, the addition of sheep wool fibers subsequently improved the tensile and flexural strength values of concrete, thereby improving the concrete ductility with higher energy absorption capacity. The microstructural characteristics of sheep wool fiber reinforced concrete were conformed to have good bonding and low voids. The findings of the study revealed that the addition of sheep wool fibers in the production of concrete is viable both technically and environmentally.

Alfalfa mosaic virus (AMV) causes significant losses in the global agricultural production of crops such as potato (Solanum tuberosum L.). Transcriptional levels of 10 innate defense genes, five related to the polyphenol biosynthetic pathway (PAL, HQT, HCT, CHS, and CHI) and five pathogenesis-related proteins (PR-1, PR-2, PR-3, PR-5 and PR-7) were investigated at different days post-inoculation (dpi). The results revealed that fluctuations in the expression of these examined defense genes between induction and suppression, especially in the first 10 dpi, are common. Interestingly, greater up-regulation of most of the tested genes at 4 dpi was associated with greater down-regulation of PR-2 and a reduction in viral coat protein (CP) accumulation. Conversely, greater activation and accumulation of the virus at 10 dpi suppressed the expressions of all genes except PR-1 (salicylic marker gene), and CHI genes showed 1.189- and 1.028-fold changes respectively. At 30 dpi, the greatest level of AMV-CP accumulation (42.27-fold) was associated with severe symptoms that started appearing at 18 dpi. Consequently, at 30 dpi, none of these genes had an effect on the presence and multiplication of the virus inside the plant cell. This study provides the first valuable information of the molecular transcriptional levels of these potato genes under AMV infection.

Laboratory experiments were conducted to investigate the effect of ground granulated blast furnace slag (GGBFS) replacement on the length change of high-performance concrete (HPC). Nine concrete mixtures at w/cm ratio of 0.33 were cast using two silica fume blended cements of different fineness and two sources of GGBFS at three levels of GGBFS replacement (25%, 35% and 50%) as well as the use of a shrinkage-reducing admixture (SRA). The length changes due to autogenous and drying shrinkage were lower for the 50% and 35% GGBFS replacement as well as by use of a shrinkage reducing admixture compared to the mixture with 25% GGBFS replacement. Furthermore, the total drying shrinkage of all the concrete mixtures tested were in compliance with the 400 microstrain shrinkage limit specified for low-shrinkage concrete in the Canadian CSA A23.1 standard. The test results have also shown that while increased fineness of the silica fume blended cement increased the compressive strength of concrete, it also resulted in increased drying shrinkage with increased cracking potential.

Preplaced aggregate concrete (PAC), also known as two-stage concrete (TSC), is a particular type of concrete that is produced by placing coarse aggregates in a form and voids amongst them are then injected with a flowable grout. The preplaced aggregate fiber reinforced concrete (PAFRC) is new developed concrete, with a unique mixture of coarse aggregates and short fibers that are premixed and preplaced in the formwork and injecting grout into the voids of the aggregate mass. The current study develops the concept of a new PAFRC reinforced with waste polypropylene (PP) carpet fibers and investigate its strength and transport properties. Palm oil fuel ash (POFA) was used as partial cement replacement. Six PAFRC mixes with fibers varying from 0 to 1.25% with a length of 30 mm were made by the gravity method. Another six batches with the similar fiber dosages were made, where the pumping method was used to inject the grout into the voids between the aggregates. The results showed that by adding carpet fibers, the compressive strength of PAFRC specimens reduced. However, the PAFRC specimens revealed a notable enhancement in the tensile strength values. Moreover, water absorption, sorptivity, and chloride penetration depth were reduced for POFA-based PAFRC specimens reinforced with carpet fibers. The study revealed that the carpet fibers are potential to be used in PAFRC by developing the transport and strength properties.