Extinction of natural resources builds up pressure on governments to invest in research to find more sustainable resources within the construction sector. Earlier studies on mortar and concrete show that bottom ash and basalt fiber are independently alternative binders in the concrete sector. This study aims to use bottom ash and basalt fiber blends as alternative novel-based composites in pure cement paste. The strength and durability properties of two different percentages of bottom ash (40% and 50%) and three volume fractions of basalt fiber (0.3%, 0.75%, and 1.5%) were used at three curing periods (7, 28, and 56 days). In order to measure the physical properties of the basalt-reinforced bottom ash cement paste composites flowability, dry unit weight, porosity, and water absorption measurements at 7, 28, and 56 days of curing were performed. Furthermore, the mechanical properties of composites were determined by unconfined compressive strength and flexural strength tests. Finally, to assess the durability, sulfate-resistance and seawater-resistance tests have been performed on composites at 28 and 56 days of curing. Results showed that the addition of basalt fiber improves the physical, mechanical, and chemical stability properties of paste up to a limiting basalt fiber addition (0.3% volume fraction) where, above, an adverse effect has been monitored. It is clear that observed results can lead to the development of sustainability strategies in the concrete industry by utilizing bottom ash and basalt fiber as an alternative binder.

The application of critical state framework depends on the presence of either a unique critical state line (CSL). However, many authors have observed that a transitional behaviour occurs in certain granular intermediate soils in which the fines content as well as the initial void ratio have a significant effect on the location of this line. This work investigates these effects in poorly graded granular soils as previous studies reported that this type of soil does not exhibit transitional behaviour. Results from this study reveal that poorly graded fine-grained sand exhibits transitional behaviour similar to that of intermediate soils and subsequently, it can be grouped into ranges of initial densities in which each group approaches a unique CSL in v:lnp' space. A unique state boundary surface is identified by determining the critical state parameters from each group and using these parameters to normalize the stress paths; this shows that the critical state framework can be successfully applied to this type of soil.

Marine clay deposits are commonly found worldwide. Considering the cost of dumping and related environmental concerns, an alternative solution involving the reuse of soils that have poor conditions is crucial. In this research, the authors examined the strength, microstructure, and wet–dry resistance of triple-binder composites of marine-deposited clays and compiled a corresponding database. In order to evaluate the wetting–drying resistance of the laboratory-produced samples, the accumulated mass loss (ALM) was calculated. The use of slag alone as a binder, at any percentage, increased the ALM up to 2%. However, the use of lime as the third binder seemed to accelerate the chemical reactions associated with the hydration of clay and cementitious material and to enhance the chemical stability, i.e., specimens that included both lime and slag experienced the same ALM as specimens treated with cement only. Scanning electron microscopy analysis confirmed the durability improvements of these clays. The proposed unconfined compressive strength–porosity and accumulated mass loss relationship yielded practical approximation for the fine- and coarse-grained soils blended with up to three binders until 60 days of curing. The laboratory-produced mixes showed reduction of embodied energy and embodied carbon dioxide (eCO2) emissions for the proposed models.

This article presents the new innovative concept for optimal design of Vertical Axis Current Turbines (VACT) applicable in low current speed which is being increasingly used to harness kinetic energy of water and convert it into other useful forms of energy as a clean and renewable energy. Widespread commercial acceptability of these turbo machines depends upon their efficiency. This largely depends upon the geometric features of the hydro turbines such as operation of designed system, joints, number and shape of blades and etc. The concept of VACT was proposed to provide a solution for the case of low current force inflow to vertical axis turbines. VACT has four suitable blades with flexible hinge joint to guide the water in come to reduce the drag force, light shaft and arms with stiff metal to make rigid and strong structure. The current study discusses the components of VAC turbine, rigidity of structure, performance, executive concept, efficiency, material, gearbox, environmental impacts and prevention of water corrosion. The new proposed innovative concept of VACT has flexible hinge connection for changing the blades directions automatically to reduce hydrodynamic drag and increase the hydrodynamic pressure to rotate the main shaft and enhance the efficiency as well. Main shaft connected to epicyclical gearbox to provide the higher torque for maximum electric power generation.

Due to the increasing presence of problematic soils, expansive clays and highly compressive sand engineers are using a verity of soil improvement techniques to treat such soils. While geosynthetics are extensively used for improving soil characteristics in roads, pavements and embankments, it can also be used to increase the lack of bearing capacity of residential housing or lightweight structures constructed on sandy soils. In order to simulate site conditions in the laboratory environment, a laboratory-scale testing platform has been manufactured to assess the behaviour of geosynthetics reinforced and un-reinforced strip footing. The first group of tests were performed on the unreinforced compacted sandy soils with different densities where the other group of tests were carried out in the soil that has been reinforced individually with three different types of geosynthetic materials having distinct tensile strengths. Furthermore, interface direct shear tests and consolidated undrained triaxial tests have been carried out to determine the shear parameters which is directly influencing the bearing capacity a strip footing. Geosynthetic reinforcement has considerably enhanced the mechanical behaviour of sandy soil in regarding the type of geosynthetic. Furthermore, it was observed that coir geosynthetic has provided increased interfacial friction when compared to other geosynthetic types and improved bearing capacity. Moreover, the adopted testing method found to represent well the behaviour of such materials in the laboratory environment.