Service Life Properties Research Articles

The Effects of Using Eco-friendly Materials for the Production of High Strength Mortar

This study aims to evaluate the effect of using eco-friendly mineral admixtures, such as calcined clay (CC), silica fume (SF), and limestone (L), as partial replacements for ordinary Portland cement (OPC) in the production of high-strength mortar(HSM). The use of these materials can help reduce the environmental impact of cement production by decreasing carbon dioxide emissions and preserving natural resources. To achieve the desired strength, different mixtures were proportioned by increasing the percentage of binder and limiting the water-to-binder ratio (w/b) with the aid of superplasticizer (SP) type G. The mechanical behavior and strength of the blended cements were evaluated, and the optimal mix was determined based on the results of mechanical behavior, strength, and flowability. The results revealed that the optimal mix that gives the best mechanical behavior is the mix F32 with combination of (8% SF + 4 %L+ 13% CC) with an increase about 35 % to control mix strength. The study concludes that using CC, SF, and L as partial replacements for OPC can improve the properties of modern concrete/mortar mixes, resulting in improved durability, service-life properties, and mechanical properties. The results of this study can be utilized as a base for future studies on the same concrete mix design.

TiO2 Passivated Zno Nanoarray Layer Based Fluoroalkylsilane Film for Photovoltaic Optical Glass: Achieving UV Shielding, Acid Rain Resistance, and Self‐Cleaning Properties

AbstractPhotovoltaic technology is a prominent source of renewable energy, but maintenance costs and efficiency attenuation of large photovoltaic devices are significant issues due to their vast energy conversion area. To reduce costs and facilitate maintenance, superhydrophobic surfaces with self‐cleaning properties have been developed for photovoltaic glass. In this study, transparent ZnO nanoarrays (NAs) are synthesized on photovoltaic glass, with Eu3+ doping enhancing the ultraviolet radiation resistance of photovoltaic devices and slightly increasing visible transmittance. A TiO2 passivation layer is introduced on the ZnO NAs surface to enhance acid resistance and mitigate corrosion caused by acidic rainwater. Fluoroalkylsilane (POTS) modification achieves superhydrophobicity with a water contact angle of 160.25°, as demonstrated by droplet rolling experiments. Micro‐interaction of superhydrophobic properties is further investigated by force curve measurement using atomic force microscope, showing almost no nanometer water moisture on the superhydrophobic surface, but conspicuous water moisture on the control glass surface. Finally, simulated models and practical silicon crystal solar cells fabricated using the self‐cleaning glass show excellent acid rain resistance, self‐cleaning, and long service life properties, with no power conversion efficiency degeneration during a 40‐day outdoor application test.

Effect of glass fiber loading and reprocessing cycles on the mechanical, thermal, and morphological properties of isotactic polypropylene composites

AbstractIn this study, a preliminary finding is carried out to obtain the optimum E‐glass fiber content in polypropylene (PP) plastic products using loadings of 5, 10, 20, 30, and 40 wt%. The formulation with the optimum loading of 10 wt% glass fiber was reprocessed 10 times via extrusion and compression molding techniques to simulate actual recycling and impacts on service life properties such as mechanical, toughness, chemical, thermal, composition, and morphology. In the result, mechanical properties were lost after each reprocessing without effect on the chemical properties and elemental compositions. The thermal studies showed a decrease in degradation temperatures with the onset degradation temperature (TOnset) for the one‐time reprocessed PP recorded at 336.93°C with a maximum rate of weight loss (TMax) at 427.68°C which further reduced to 259.90°C (TMax of 388.47°C) after 10 extrusion run showing one‐step decomposition patterns. This work provides that glass fiber‐reinforced plastics should not be reprocessed beyond 3 times except when refreshed with the addition of virgin PP to make up for the lost property. This will be very useful for manufacturers who want to simultaneously save costs (retain profit margin) and maintain the environment.

Influence of non-adsorbing polymers on drying of fresh mortars

In this paper, we compare the drying of non-reactive materials (glass beads packing) with the one of fresh mortars. Through the sample drying process, the existing literature on the general underlying physical processes involved in drying of porous media allows for the identification of two distinct regimes. These regimes drive the drying kinetics. We then measure the drying kinetics of the same materials containing polymers, which do not absorb on the cement grains. Our results and analysis suggest that the increase in the viscosity of the interstitial water due to polymer addition is at the origin of a decrease in drying rate. As drying of fresh cementitious materials strongly impacts the final properties in configuration with large exposed surfaces, we suggest that such polymer addition could slow down the overall drying of cementitious materials and improve their service life properties.