Impact of Wetting–Drying Cycles on the Mechanical Properties and Microstructure of Wood Waste–Gypsum Composites

Abstract

Large amounts of wood waste are generated each year in the world. In an attempt to identify a good recovery option for those residues, wood waste from construction and demolition works were used as raw materials in gypsum plasters. However, wood is a biodegradable material which implies that the products or materials that contain it are susceptible to suffering an important deterioration, due to exposure in certain environments. For that reason, the aim of this work was to simulate the effects that, in the long term, the atmospheric exposure of wood waste–gypsum composites would have. To do that, the plasters were subjected to 5, 10, and 15 wetting–drying cycles in a climatic chamber. In this study, the density, flexural and compressive strength, and ultrasonic velocity of these composites were determined by the influence of the aging process on their mechanical properties. Furthermore, in order to detect changes on their internal structure, scanning electron microscopy tests (SEM) were used. The results showed that they were suitable to be used as indoor coverings of buildings. However, a treatment to reduce the moisture absorption of the wood waste must be studied if mixtures with high percentages of wood shavings (WS20) are used in wet rooms.

Gypsum Mortars with Acacia dealbata Biomass Waste Additions: Effect of Different Fractions and Contents

“…These different characteristics will also affect chemical and physical interactions with other mortar components, thus influencing mechanical properties. This tendency for a decrease in mechanical properties with the addition of biomass was already observed by other authors [41,42]. Morales-Conde [43] found that not exceeding 5% of sawdust incorporation on gypsum mortars led to an improvement of flexural strength, whereas all the percentages of sawdust additions decreased the compressive strength.…”

Comparative Analysis of Cellulose, Hemicellulose and Lignin on The Physical and Thermal Properties of Wood Sawdust for Bio-Composite Material Fillers

“…Lignin is a heterogeneous compound consisting of the elements carbon (C), hydrogen (H), and oxygen (O). In contrast to cellulose, which is formed from carbohydrate groups, lignin is formed from an arrangement of aromatic groups linked to each other by aliphatic chains [22,23]. The carbonyl content is very dominant in the aromatic group.…”

Mechanical properties, thermal properties and durability of lightweight thermal insulation recycled concrete

“…Waste wood in the use of wood chips to replace fine aggregates in the preparation of mortar and concrete found that with the increase in the amount of wood chips doped wood chips and the interface between the pulp increases, the density of the concrete was gradually reduced, the compressive strength was gradually decreased, the drying shrinkage was diminished, and the resistance to cracking ability was enhanced. Among them, when the proportion of wood chips substitution was 10%, the compressive strength was reduced by about 10%; when the proportion of substitution was 60%, the compressive strength is reduced by about 40% [20][21][22][23][24]. Whereas, the preparation of wood fiber-based concrete using waste wood found that wood fiber addition can significantly increase the mechanical strength of concrete, especially the flexural strength.…”