Excellent mechanical properties and chemical stability make carbon nanotubes (CNTs) some of the most promising nanomaterials that can be used in cementitious composites to improve their performance. However, the difficulty of CNTs’ dispersion within the cementitious structure still exists and thus prevents the homogeneous distribution of CNTs. The homogeneous distribution of CNTs within a composite structure plays an essential role that can have a positive effect on the mechanical performance of CNT-cement composites. This paper introduces the methods for the production of CNTs and provides useful information about the influence of CNTs on the flowability, mechanical performance, microstructural changes and hydration of cement composites. The influences of water-cement ratio, used surfactants and various doses of CNTs on the properties of cementitious composites were also studied.

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Laterite, due to its wide availability and low cost, is considered as a societal building material in tropical and sub-tropical regions of the world. Excavation of the laterite leaves laterite stones as scrap which accounts for around 25-30%. These scraps being a hindrance for the further excavation of the laterite in the quarries can be crushed and used to meet the demand of fine aggregates in the construction industry. Performance indicators such as workability, compressive, split-tensile and flexural strength are measured to evaluate the suitability. M30 grade of concrete specimens were produced with these crushed scraps by replacing M-sand at the intervals of 25% ranging from 0% to 100%. Laterite replacement of 25% could enhance the performance after 28 days. Not limiting only to strength characteristics, its morphological features were also understood by conducting Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-Ray Diffraction (XRD) and Thermogravimetric analysis (TGA) for the optimum mixes. Laterite, due to its wide availability and low cost, is considered as a societal building material in tropical and sub-tropical regions of the world. Excavation of the laterite leaves laterite stones as scrap which accounts for around 25-30%. These scraps being a hindrance for the further excavation of the laterite in the quarries can be crushed and used to meet the demand of fine aggregates in the construction industry. Performance indicators such as workability, compressive, split-tensile and flexural strength are measured to evaluate the suitability. M30 grade of concrete specimens were produced with these crushed scraps by replacing M-sand at the intervals of 25% ranging from 0% to 100%. Laterite replacement of 25% could enhance the performance after 28 days. Not limiting only to strength characteristics, its morphological features were also understood by conducting Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-Ray Diffraction (XRD) and Thermogravimetric analysis (TGA) for the optimum mixes.

This research work is an insight into the various properties of liner materials utilized in landfill sites to control the leachate. Although expansive clay soil is inorganic, it is problematic. The soil owes this aspect to erratic fluctuations in its behavior due to the movement of water. Urbanization, increase in population and industries generate enormous amounts of waste in different forms. Disposal of these wastes in the landfill without any scientific manner creates a major problem to the surrounding soil and groundwater. In this study, an attempt was taken to identify the effect of soil properties and groundwater quality due to the continuous generation of leachate in the dumping sites. To prevent such an environmental problem, highly impermeable sand–bentonite mixture is used as a liner material in the waste disposal sites. Therefore, various mixtures of sand–bentonite were prepared by varying sand contents and different sieve sizes, i.e. 2–0.075[Formula: see text]mm; 2–0.425[Formula: see text]mm and 0.425–0.075[Formula: see text]mm were used. And also to improve the strength and hydraulic conductivity of the liner materials, discrete random fiber is mixed with various proportions to these mixtures and examined.