In this paper, we reviewed the existing literature on the fabrication of nanocomposites based on cellulose and cellulose nanocrystals (CNCs), and analyzed their dispersion mechanism with respect to their use in the field of construction. First, the existing literature on CNC-based nanocomposites that exhibit the physical and chemical properties of nanocellulose and CNCs was reviewed. Next, keeping the use of these nanocomposites in the field of construction in mind, we determined the optimal mechanical method for their dispersion as an alternative to the currently used harmful chemical techniques. To this end, we evaluated the dispersibility of colloidal CNCs using two dispersion methods: magnetic stirring (for stirring times of 60 min, 120 min, and 180 min) and high-pressure dispersion (at pressures of 345 × 10 5 Pa, 1035 × 105 Pa, and 1587 × 10 5 Pa, and one to three dispersion passes). The optimal dispersion conditions were determined by analyzing the size and zeta potential of the CNC particles. It was found that the difference in the average diameter was reduced by approximately 76% at 1587 × 10 5 Pa during high-pressure dispersion. modulus of 200-220 GPa, density of approximately 8 g/cm 3 .) While the process for producing CNCs is a complex one, the final product suggests improvements in the cement composites by improving mechanical properties. Calcium silicate hydrate (CSH) gel formation was improved in CNC cement mortar, with the compressive strength of the mortar being 42-45% higher than that of conventional cement mortar. The formation of the CSH gel improved the strength of the cement by improving its hydration. In order to quantify the performance of cement composites based on CNCs, their degree of hydration was measured using an isothermal calorimeter and a thermogravimetric analyzer [18,19].Studies on the application of cement to conventional CNCs have been carried out only in some strength studies using optimal mixing conditions. Ultrasonic methods are primarily used to disperse CNCs [16,[18][19][20][21]. However, ultrasonic dispersion techniques have certain limitations with respect to the production of cement paste and mortar, because they can only produce small amounts of CNC suspensions (10-250 mL by Sonics and Processor USA). When attempting to produce large amounts of CNC suspensions, as is the case when making concrete mixtures, the ultrasonic dispersion equipment may exhibit problems caused by prolonged use.Therefore, methods should be developed that allow one to prepare CNC-based concrete on a large scale while causing fewer equipment problems. In this study, we attempted to determine the optimal CNC dispersion conditions based on an evaluation of the previously reported dispersion data with the aim of using CNCs as a construction material. Review of Existing ResearchWe reviewed previous studies on cellulose and cellulose nanomaterials that are relevant to the field of construction. Table 1 summarizes the review of the existing literature on CNCs.

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In the past few decades, there have been numerous attempts to add plastic aggregates composed of polymeric materials to cementitious composites, either as an alternative to using natural aggregates or as fillers and fibers. However, the addition of plastic aggregates often results in cementitious composites with lower mechanical performance. In this paper, we attempt to address this issue by applying gamma irradiation technology to restore the mechanical performance. We aimed to determine the optimal gamma irradiation and mixing combinations by comparing the experimental results with information summarizing the recent literature related to the use of gamma-irradiated plastic aggregates within cementitious composites. To this end, the effects of changes in the physical and chemical properties of plastics due to irradiation with gamma irradiation on the strength of cementitious composites were evaluated using irradiation doses of 25, 50, 75, and 100 kGy and various plastic materials as key parameters. In the compressive strength test, it was found that adding gamma-irradiated plastic increased the compressive strength of the cementitious composites compared to the nonirradiated plastic. This suggests that the irradiation of plastic aggregates with gamma rays is an effective method to recover some of the strength lost when plastic aggregates are added to cementitious composites. In addition, modifications in the microstructure and chemical properties of the gamma-irradiated plastic were analyzed through SEM and FT-IR analysis, which allowed the determination of the strength enhancement mechanism. The results of this study show the possibility of the state-of-the-art performance improvement method for using plastic aggregate as a substitute for natural aggregate, going further from the plastic performance improvement technology for limited materials and radiation dose presented in previous studies.

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Recently, pollution caused by an increasing amount of worldwide plastic waste has become a global problem. However, these concerns can be alleviated by the use of gamma-ray technology. Using radiation technology, plastic wastes can be converted into a variety of useful purposes presenting powerful opportunities for environmental sustainability and material innovations. Plastics are strong, durable, waterproof, lightweight, easy to mold, and recyclable. In this study, plastic aggregate modified by gamma irradiation was mixed into cement composites, and mechanical property evaluation experiments were conducted. As a result, it was confirmed that the physical performance of cement composites was improved by up to 70% in the case of using the modified plastic aggregates compared to the general plastic aggregate.