Improving the Durability of Lime Finishing Mortars by Modifying Them with Silicic Acid Sol

Recyclable Materials for Ecofriendly Technology

This Special Issue (SI), "Recyclable Materials for Ecofriendly Technology", has been proposed and organized as a means to present recent developments in the field of environmentally friendly designed construction and building materials. For this purpose, dozens of articles were included or considered for inclusion in this SI, covering various aspects of the topic. A comparison of these articles with other modern articles on this topic is carried out, which proves the prospects and relevance of this SI. Furthermore, per the editorial board's journal suggestion, the second volume of this successful SI is being organized, in which authors from various countries and organizations are invited to publish their new and unpublished research work.

Performance Investigation of the Incorporation of Ground Granulated Blast Furnace Slag with Fly Ash in Autoclaved Aerated Concrete

Autoclaved aerated concrete (AAC) is one of the most common types of lightweight cellular concrete, having a density of approximately one-fourth of that of conventional plain cement concrete. The use of industrial waste materials in concrete as a replacement for cement has garnered a lot of attention in recent years as a way to reduce the environmental effect of concrete. In this study, an attempt has been made to study the effect of AAC blocks made of industrial wastes such as fly Ash (FA) and ground granulated blast furnace slag (GGBS). Fly ash, along with different dosages of GGBS, was used as a partial replacement for cement in the production of AAC. For all the different dosages, microstructural analysis was performed using a Scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDAX), and Fourier transform infrared spectroscopy (FTIR). Mechanical performances of AAC were determined by conducting various tests like compressive strength, modulus of rupture, dry density, and water absorption. The results revealed that the dosage of “15% GGBS + 85% cement” has maximum compressive strength, modulus of elasticity, and modulus of rupture made of Class F Fly Ash when compared to Class C Fly Ash based AAC blocks. Besides, the incorporation of GGBS in the manufacturing process would increase the compressive strength of AAC up to 68%. Hence, it is recommended to use 15% GGBS + 85% cement as a potential rate of replacement, to improve the mechanical properties of AAC blocks significantly.

Effect of Steel Fiber on the Strength and Flexural Characteristics of Coconut Shell Concrete Partially Blended with Fly Ash

The construction industry relies heavily on concrete as a building material. The coarse aggregate makes up a substantial portion of the volume of concrete. However, the continued exploitation of granite rock for coarse aggregate results in an increase in the future generations’ demand for natural resources. In this investigation, coconut shell was used in the place of conventional aggregate to produce coconut shell lightweight concrete. Class F fly ash was used as a partial substitute for cement to reduce the high cement content of lightweight concrete. The impact of steel fiber addition on the compressive strength and flexural features of sustainable concrete was investigated. A 10% weight replacement of class F fly ash was used in the place of cement. Steel fiber was added at 0.25, 0.5, 0.75, and 1.0% of the concrete volume. The results revealed that the addition of steel fibers enhanced the compressive strength by up to 39%. The addition of steel fiber to reinforced coconut shell concrete beams increased the ultimate moment capacity by 5–14%. Flexural toughness was increased by up to 45%. The span/deflection ratio of all fiber-reinforced coconut shell concrete beams met the IS456 and BS 8110 requirements. Branson’s and the finite element models developed in this study agreed well with the experimental results. As a result, coconut shell concrete with steel fiber could be considered as a viable and environmentally-friendly construction material.

Effects of Admixtures on Energy Consumption in the Process of Ready-Mixed Concrete Mixing

The production and utilization of concrete and concrete-based products have drastically increased with the surge of construction activities over the last decade, especially in countries such as China and India. Consequently, this has resulted in a corresponding increase in the energy used for the production of ready-mixed concrete. One approach to reduce the cost of concrete manufacturing is to reduce the energy required for the manufacturing process. The main hypothesis of this study is that the power required for mixing the concrete can be reduced through the use of mineral admixtures in the mix design. Optimization of energy consumption during mixing using admixtures in concrete manufacturing is the predominant focus of this article. To achieve this objective, power consumption data were measured and analyzed throughout the concrete mixing process. The power consumption curve is the only source to distinguish the behavior of the different materials used in the concrete in a closed chamber. In the current research, fly ash and ground granulated blast-furnace slag (GGBS) were used as mineral admixtures to produce ready-mixed concrete. The experimental study focused on the influence of GGBS and fly ash on power consumption during concrete mixing. The results indicated that the use of a higher content of GGBS is more beneficial in comparison to the use of fly ash in the mix due to the lower mixing time required to achieve homogeneity in the mixing process. It was found that the amount of energy required for mixing is directly related to the mixing time for the mix to achieve homogeneity.