Enhanced water durability of phosphor-in-glass (PiG) basing on SnCl2–P2O5 glass matrix induced by adding ZnO

Phosphor-in-glass (PiG) composed of glass matrix and the embedded phosphor particles has been intensively developed to meet the requirement of high-power LED lighting sources. P2O5-based glass matrices are the promising candidates to fabricate high luminescence PiG in view of their low-melting temperature to avoid the erosion of phosphor by glass melting, however, their poor chemical durability limited the practical application. In this work, the water durability of PiG basing on SnCl2–P2O5–ZnO glass matrix embedded with YAG: Ce[Formula: see text] phosphor is demonstrated. With the addition of ZnO, the water durability of SnCl2–P2O5- based PiG is enhanced significantly without obvious loss of light output. The influence of ZnO addition with variable contents on the microstructure, photoluminescent properties and the water durability of the obtained PiG is investigated through a series of characterizations. The obvious improvement of the water erosion resistance induced by adding ZnO provides an optional route to develop higher stability, lead-free, cost-effective low-melting point P2O5-based glass matrix for fabrication of high performance PiG materials.

Recyclability, durability and water vapour adsorption of unstabilised and stabilised compressed earth bricks

This paper investigates the recyclability, liquid water durability and water vapour adsorption of both unstabilised and stabilised compressed earth bricks. Stabilised bricks were manufactured by adding either cement or the biopolymer guar gum to the base earth. Unconfined compressive strength tests were then performed on both unstabilised and stabilised earth bricks manufactured with recycled material (i.e. material taken from the failed compressed earth bricks after the compressive strength tests). These tests enabled to assess the influence of recycling on the stiffness, strength and strain energy of all compressed earth bricks. Immersion and drip tests were subsequently performed to investigate the effect of cement and biopolymer stabilisation on the durability of the compressed earth bricks against the weathering action of water. An additional set of laboratory experiments was finally conducted by means of a Dynamic Vapour Sorption (DVS) system to study the effect of earth stabilisation on the capacity of adsorbing/releasing water vapour as the ambient humidity changes. Outcomes from this experimental campaign showed that both unstabilised and biopolymer stabilised earth bricks maintained a similar mechanical performance after recycling, while cement stabilised bricks showed a remarkable reduction of both stiffness and strength. Finally, both cement and biopolymer stabilised bricks improved the liquid water durability while reducing the water vapour adsorption compared with the unstabilised earth bricks. Results from this experimental work will be useful for life cycle assessments, especially for modelling the end-of-life of the material as well as its potential reuse.

Influence of particle grading on the hygromechanical properties of hypercompacted earth

Civil engineering research is increasingly focusing on the development of sustainable and energy-efficient building materials. Among these materials, raw (unfired) earth constitutes a promising option for reducing the environmental impact of buildings over their entire service life from construction to demolition. Raw earth has been used since old times but only recently has acquired prominence in mainstream building practice. This is mainly because of the development of novel methods to enhance the mechanical, hygroscopic and durability properties of compacted earth without increasing carbon and energy footprints. In this context, the present paper studies the dependency of the strength, stiffness, moisture capacity and water durability of compacted earth on particle grading. Results indicate that the particle size distribution is a key variable in defining the hygromechanical characteristics of compacted earth. The effect of the particle size distribution on the hygromechanical properties of compacted earth may be as important as that of dry density or stabilisation. This study suggests that a fine and well-graded earth mix exhibits higher levels of strength, stiffness, moisture capacity and water durability than a coarse and poorly-graded one.