Materials Science Forum Vol. 1142

Abstract: The purpose of this study is to investigate the influence of the cement/sand (c/s) ratio on the behavior of cement mortar. The used c/s ratios in this study were 1:0, 1:0.45, and 1:0.83. The findings of this study showed that increasing the sand content reduces the compressive strength of the mortar mixture by 41.5 and 28.2% for the c/s ratios of 1:0.45, and 1:0.83, compared to the plain cement mortar (c/s: 1:0). The increase in sand content requires more water content to increase the workability and strength of the mixtures. However, the flexural strength slightly increased compared to the control mortar. In addition, to enhance sustainability, the cement was replaced with two waste industrial materials namely, micro silica (MS) and fume treatment plant (FTP) dust by 20% of cement weight. The modified mixtures (c/s: 1:0) also showed reduced strength at the testing age. The compressive strength of the modified mixtures was reduced by 50% and 19% for the FTP and MS-modified mixtures, respectively. On the other hand, the flexural strength was reduced by 19.1 and 30.2% for the FTP and MS-modified mixtures. This reduction can help achieve certain strength requirements by lowering the cement content in cement concrete mixtures.

Abstract: When discussing graphene materials, their mechanical strength, impermeability, flexibility, thermal and electrical conductivity, and lightness are key reference points, earning them the moniker "all-in-one material. “This versatility makes graphene suitable for various applications, including electronics, medicine, plastics, coatings, construction, and renewable energies. However, it's crucial to note that the behavior of these materials at the nanometric scale depends on factors such as the type of graphene, functionalization, concentration, and the specific processes involved in each industry. Since the isolation of graphene in 2004, significant efforts have been made to comprehend its multifunctional properties. Nevertheless, the primary challenge lies in translating this knowledge from the laboratory to industrial applications, hampered by the high cost and low yield of graphene. Fortunately, the construction industry, particularly the concrete and coatings sector, appears to be one of the most promising fields for the integration of this nanotechnology. In this context, we present a diverse array of representative trials conducted on various concrete designs and environmentally friendly, antimicrobial, and anticorrosive coatings enhanced with graphene materials. These trials showcase the multifunctional enhancement of properties thanks to the incorporation of graphene materials in different commercially available products tailored for industrial applications, demonstrating that graphene not only represents a technological innovation but is also a catalyst for more sustainable practices in various industries. Its ability to improve the efficiency of different products and applications, becomes graphene as a key material in the immediate future with which industries operate within ecological limits while meeting human needs.

Abstract: Warm-Mix Asphalt (WMA) additives are used to improve the performance and workability of the asphalt binders. This study used a nano-based saline, Zycotherm, to reduce the viscosity and improve the high-temperature performance of the asphalt binders. To investigate the impact of Zycotherm, penetration, softening point, viscosity and Dynamic Shear Rheometer (DSR) rutting parameter tests were carried out. Based on the results, the Zycotherm-modified asphalt binder with a percentage of 3% lowered the penetration by around 40% and the softening point by 4%, while increased the viscosity by 10% when compared to the control asphalt binder. Rheological testing showed a decrease in the complex shear modulus value and a decrease in the phase angle by around 24% for the Zycotherm modified asphalt binder, which means that the rutting resistance decreases by 13%. Zycotherm modified asphalt binder with a percentage of 1.5% showed nearly similar results as the 3% in terms of lowering the penetration by 20% and softening point by 2% while increased the viscosity even more than the 3% Zycotherm by an overall percentage increase of 11% when compared to the control asphalt binder. For the Rheological testing, the Zycotherm modified asphalt binder with a percentage of 1.5% also showed a 12% decrease in phase angle and complex shear modulus values.

Abstract: In response to the rapid urbanization and local boom in UAE’s development and real estate industry, concrete is continuously in demand in alarming amounts contributing to the climate change effect. Research has continuously shown that lightweight concrete (LWC) is a potential sustainable alternative for normal weight concrete (NWC) due to incorporation of cement alternatives within the mix, higher resource efficiency, and enhanced thermal insulation. This paper investigates the residual properties of NWC and structural LWC at room temperature and when exposed to the following steady-state temperatures: 100°C, 200°C, 400°C, 600°C, and 800°C. Results show that LWC exhibit higher fire performance than NWC. At failure, NWC specimens majorly reported cone and split failure modes. The LWC specimens displayed mostly columnar failure modes. Spalling of concrete was first reported at 600°C on LWC at the corners of the specimens. At 800°C, surface spalling was reported on NWC only, indicating the higher fire resistive property of LWC. After heat exposure, discoloration was first observed in all specimens at 400°C. The compressive strength of both types of concrete initially increased after high-temperature exposure. Residual strength reported increase up to 200°C and 400°C for NWC and LWC, respectively. Consequently, significant decrease in compressive strength reaching around 20% of the original compressive strength when exposed to 800°C. Results showed that NWC experiences more reduction in residual strength than LWC, supporting that LWC is a promising construction material in enhancing structural fire safety.

Abstract: The use of plastic waste can enhance the properties of asphalt binders and mixes while solving one of the most environmental-related issues. Waste plastic from milk bottles consisting mainly of high-density polyethylene (HDPE) waste was used in this research work to modify asphalt binder with two doses (2% & 4% by weight of asphalt binder). The asphalt binder's performance grade (PG) was determined and fed into AASHTOWare Pavement ME Design software to simulate pavement performance under Sharjah, UAE climate conditions. Testing results showed that adding HDPE boosted the PG from 64 to 76 and 82 for 2% and 4% dosages, respectively. AASHTOWare Simulation runs showed that 2% HDPE dosage could extend the expected service life of the asphalt pavement by 0.3 years compared to the control section, while 4% HDPE can add nearly 10.8 years to the pavement design life. Compared to the control, 2% and 4% HDPE also decreased the percentage of bottom-up cracks by 0.37% and 2.94%, respectively. When comparing the 2% and 4% HDPE-modified asphalt binders versus the control one, the failure in total permanent deformation of the 3-inch asphalt concrete (AC) pavement section was reduced by 0.03 and 0.13 inches, respectively. Adding 4% helped minimize rutting by 0.25 inches compared to the control pavement section, whereas adding 2% HDPE in the 6-inch layer increased rutting by 0.15 inches. Overall, the addition of HDPE significantly improved the performance grade and durability of the asphalt binder, extending pavement life and reducing cracks and rutting, thereby contributing to more sustainable pavement solutions.