Q Qingliang Yu

Design of a novel photocatalytic gypsum plaster : with the indoor air purification property

This article addresses the design of a new photocatalytically active gypsum plaster. A hemihydrate in beta type is used as binder to design this material and a carbon modified TiO2 that can be activated by visible light is used as photocatalyst. An own developed test setup to assess the indoor air purification capacity of the developed material is presented. The new product possesses the indoor air pollutants removal capacity. The air pollutants removal ability is related with not only the dosage of the applied photocatalyst but also strongly with the physical property of the resulting matrix such as the porosity.

Experimental Study and Modeling of the Photocatalytic Oxidation of No in Indoor Conditions

Heterogeneous photocatalytic oxidation (PCO) has shown to be a promising air purifying technology. Nitrogen monoxide (NO) is one common indoor air pollutant. The present paper addresses the PCO reaction in indoor conditions using NO as target pollutant with the gypsum plasterboard as a special substrate and carbon-doped TiO2 as photocatalyst. A photocatalytic reaction setup is introduced for the assessment of the indoor air quality. The PCO effect of the carbon-doped TiO2 is evaluated using different light wavelengths. Furthermore, the influence of the reactor volume on the PCO rate is studied. The Langmuir-Hinshelwood model is applied to describe the photocatalytic reaction mechanism. Experimental results show the validity of the L-H model in the present research. Using this model, a mathematical expression is proposed to describe the concentration change in the reactor.

Design of ultra-lightweight concrete: towards monolithic concrete structures

This study addresses the development of ultra-lightweight concrete. A moderate strength and an excellent thermal conductivity of the lightweight concrete are set as the design targets. The designed lightweight aggregates concrete is targeted to be used in monolithic concrete facade structure, performing as both load bearing element and thermal insulator. The developed lightweight concrete shows excellent thermal properties, with a low thermal conductivity of about 0.12 W/(m·K); and moderate mechanical properties, with 28-day compressive strengths of about 10-12 N/mm 2. This combination of values exceeds, to the researchers’ knowledge, the performance of all other lightweight building materials. Furthermore, the developed lightweight concrete possesses excellent durability properties.

Design of a Novel Calcium Sulfate-Based Lightweight Composite: Towards Excellent Thermal Properties

This article addresses the design of a self-compacting gypsum-based lightweight composite (SGLC). A β-hemihydrate is used as binder and lightweight aggregate (LWA, 0-2 mm in different size ranges) is used as aggregate into this composite. The mix of the new composite is designed based on the particle size distribution grading theory applying the modified Andreasen and Andersen (A&A) grading line to obtain an optimal packing of all the used solid materials. The thermal behavior of the new developed composite is investigated, from its thermal physical properties and fire behavior. The study demonstrates that this new composite has significant improvement compared to those of traditional gypsum plasterboard.

Heterogeneous photocatalysis applied to indoor building material : towards an improved indoor air quality

In the present article, kinetics of the photocatalytic oxidation (PCO) of nitric oxide (NO, as a typical air pollutant) is addressed. An extended Langmuir-Hinshelwood reaction rate model is proposed to describe the PCO of NO under indoor air conditions. The derived model incorporates the influence of the indoor air conditions in the process of the PCO. The good agreement between the predictions from the model and experimental results indicates the validity of the proposed model.

Evaluating an eco-olivine nanosilica as an alternative silica source in alkali-activated composites

In this study, an eco-olivine nanosilica is produced from natural olivine, and then used as an alternative silicate source in synthesizing the silicate-based alkali activator. The effects of silicate origin and dosage on activator characteristics, fresh behaviors, gel structure, strength, porosity, and shrinkage are investigated. The results indicate that the soluble silica content in the alternative activators is above 98%; compared with the traditional waterglass-based mixes, the nanosilica-derived ones exhibit similar behaviors in the early age reaction, gel structure, and mechanical properties. As some important engineering properties, nanosilica-based mixtures also exhibit increased workability, prolonged setting time, slightly increased porosity, and shrinkage. Thus, by using this alternative silica source in alkali-activated materials, a more sustainable product with less cost and carbon emission can be achieved, and with comparable key performances.