Publications

During the transition of one material from macro- to nano-range size, considerable changes occur in the electron conductivity, optical absorption, mechanical properties, chemical reacting activity, and surface morphology. These changes can be advantageous in the production of new mixture composites. Due to the need for developing improved infrastructure, new and high-performance materials should also be developed. In this regard, to improve the performance of concrete mixtures, several methods have been investigated, including using nanoparticles (NPs) to enhance various characteristics of the concrete composite like improving fresh and mechanical properties of self-compacting concrete (SCC) as well as improving permeability and absorption capacity of the composite by providing extremely fine particles to fill micro-pores and voids. In this paper, a state-of-the-art review was carried out on the influence of various NPs inclusion on the fresh, mechanical, and durability properties of self-compacting mortars (SCM). So that current and most recent studies previously published were investigated to highlight the influences of different NPs on the slump flow diameter, V-funnel flow time, compression and flexural strengths, water absorption, chloride penetration, and electrical resistivity. Moreover, the main section of this study was devoted to proposing different models, including nonlinear model (NLR), multi-logistic model (MLR), and artificial neural network (ANN), to predict the compressive strength (CS) of SCMs modified with NPs. Based on the analyzed data, it was illustrated that the addition of NPs into SCMs significantly enhances the fresh, mechanical, and durability performance of SCMs. Moreover, the microstructure of SCMs was considerably improved due to the higher specific surface area of NPs and their reaction with undesirable C–H which present in the cement paste matrix to produce additional C-S-H gel.

Shear damage is a catastrophic failure in the design of reinforced concrete structural elements. To prevent it, the effect of aluminum wastes on reinforced concrete shear beams was investigated in this study. There is a gap in the scientific field on the expanding concrete with aluminium waste, and no research has been done on the utilizing of aluminum waste to produce expandable concrete. Moreover, there is a gap in expandable concrete usage with aluminum waste reinforcing, which is crucial for engineering applications especially beams, slabs and columns. For this purpose, experimental investigations were performed on a total of 12 Reinforced Concrete Beams (RCB) with different aluminum waste ratio (0, 1, 2 and 3 vol.%) and different shear reinforcement spacing (270, 200 and 160 mm). The depth span ratio was chosen as 1.6, 2.0 and 2.7. RCB was simply supported on the loading frame and subjected to four-points bending. As a result of experimental tests for each sample, the maximum load, stiffness, ductility and energy dissipation capacity were calculated. It was observed that the load capacity of the Al refuse combined RCBs raises as the vacancy of the stirrup reinforcement reductions compared with reference RCBs. Furthermore, it was found that the load capacity of the RCBs reduced as the Al refuse quantity in the concrete mixture was increased from 0% to 3%. However, it was found that the decrease in load capacity for 1 vol.% aluminum waste could be tolerated. For this reason, it can be stated that aluminum waste (AW) in reinforced concrete shear beams will contribute to the beam up to 1%.

Shear walls have high strength and stiffness, which could be used at the same time to resist large horizontal loads and weight loads, making them pretty beneficial in several structural engineering applications. The shear walls could be included with openings, such as doors and windows, for relevant functional requirements. In the current study, a building of G + 13 stories with RC shear walls with and without openings has been investigated using ETABS Software. The seismic analysis is carried out for the determination of parameters like shear forces, drift, base shear, and story displacement for numerous models. The regular and staggered openings of the shear wall have been considered variables in the models. The dynamic analysis is carried out with the help of ETABS software. It has been observed that shear walls without openings models perform better than other models, and this is in agreement with the previous studies published in this area. This investigation also shows that the seismic behaviour of the shear wall with regular openings provides a close result to the shear wall with staggered openings. At the roof, the displacement of the model with regular openings was 38.99 mm and approximately 39.163 mm for the model with staggered openings. However, the model without a shear wall experienced a displacement of about 56 mm at the roof. Generally, it can be concluded that the openings have a substantial effect on the seismic behaviour of the shear wall, and that should be taken into consideration during the construction design. However, the type of opening (regular or staggered) has a slight effect on the behaviour of shear walls.

This paper reports the results of a study conducted to examine the impacts of adding graphene oxide (GO) to GBFS-fly ash-based geopolymer concrete. The geopolymer concrete’s compressive strength, thermal conductivity, and modulus of elasticity were assessed. X-ray diffraction (XRD) analysis was conducted to understand the differences in mineralogical composition and a rapid chloride penetration test (RCPT) to investigate the changes in the permeability of chloride ions imposed by GO addition. The results showed that adding 0.25 wt.% GO increases the modulus of elasticity and compressive strength of GBFS-FA concrete by 30.5% and 37.5%, respectively. In contrast, permeability to chloride ions was reduced by 35.3% relative to the GO-free counterparts. Thermal conductivity was decreased as GO dosage increased, with a maximum reduction of 33% being observed in FA65-G35 wt.% samples. Additionally, XRD showed the suitability of graphene oxide in geopolymer concrete. The present research demonstrates very promising features of GO-modified concrete that exhibit improved strength development and durability compared to traditional concrete, thus further advocating for the wider utilization of geopolymer concrete manufactured from industrial byproducts.

In recent years, textile reinforcement has been widely researched and used in reinforced concrete beams, slabs, and thin plates. However, the design for bending is completely different from that of the shear case. The use of textile carbon yarns in place of or in addition to traditional steel stirrups to reinforce the shear has been investigated. Eight beams with dimensions of 200 mm × 300 mm × 1500 mm were used in this investigation. These beams were tested in shear under four load points. Two specimens were used with and without steel stirrups as reference specimens, while the other six beams used textile carbon yarns instead of steel stirrups. The variables of this study were the length of overlap, which was 30%, 60%, and 100%, the spacing was 90 mm and 130 mm, while inclination was 45 ° and 90 °, and bonding with or without steel fibers. The results showed that using 100% overlap length, 90 mm spacing, a 45° angle, and adding steel fibers increased the shear capacity, increased the deflection, and made the cracking behavior better.

In the last few decades, the concrete industry has been massively expanded with the adoption of various kinds of binding materials. As a substitute to cement and in an effort to relieve ecofriendly difficulties linked with cement creation, the utilization of industrial waste as cementitious material can sharply reduce the amount of trash disposed of in lakes and landfills. With respect to the mechanical properties, durability and thermal behavior, ground-granulated blast-furnace slag (GGBS) delineates a rational way to develop sustainable cement and concrete. Apart from environmental benefits, the replacement of cement by GGBS illustrates an adequate way to mitigate the economic impact. Although many researchers concentrate on utilizing GGBS in concrete production, knowledge is scattered, and additional research is needed to better understand relationships among a wide spectrum of key questions and to more accurately determine these preliminary findings. This work aims to shed some light on the scientific literature focusing on the use and effectiveness of GGBS as an alternative to cement. First and foremost, basic information on GGBS manufacturing and its physical, chemical and hydraulic activity and heat of hydration are thoroughly discussed. In a following step, fresh concrete properties, such as flowability and mechanical strength, are examined. Furthermore, the durability of concrete, such as density, permeability, acid resistance, carbonation depth and dry shrinkage, are also reviewed and interpreted. It can be deduced that the chemical structure of GGBS is parallel to that of cement, as it shows the creditability of being partially integrated and overall suggests an alternative to Ordinary Portland Cement (OPC). On the basis of such adjustments, the mechanical strength of concrete with GGBS has shown an increase, to a certain degree; however, the flowability of concrete has been reduced. In addition, the durability of concrete containing GGBS cement is shown to be superior. The optimum percentage of GGBS is an essential aspect of better performance. Previous studies have suggested different optimum percentages of GGBS varying from 10 to 20%, depending on the source of GGBS, concrete mix design and particle size of GGBS. Finally, the review also presents some basic process improvement tips for future generations to use GGBS in concrete.

Ultra-high-performance geopolymer concrete (UHPGPC) was investigated in this paper using microsilica and granulated blast furnace slag (GBFS) comprising polypropylene fiber (PF) and steel fiber (SF). The first group of mixing ratios was used to develop a control mixture with maximum compressive strength for this purpose. In the second group, nine mixtures were used to evaluate the effect of the fibers on the compressive strength, split strength, flexural strength, and modulus of elasticity of UHPGPC. Furthermore, the SEM analyses were performed to understand the mechanism of strength improvement based on the reaction products and micromorphology. The results indicate that the presence of PF in samples containing SF enhances its mechanical properties. Moreover, the results indicate that replacing PF with SF reduces mechanical strength while increasing durability.