Alternative vibro-dynamic compression processing of wood-cement composites using Amazonian wood

Abstract

Wood-cement composite (WCC) is a potential construction material for tropical regions, due to its physico-mechanical properties and resistance to decay and fungi attack. However it is important to test alternative production methods and wood materials that are easier and cheaper than those traditionally used, in order to create a higher demand for this product. The aim of this work was to evaluate the use of wood from four Amazonian species (Eschweilera coriaceae, Swartzia recurva, Manilkara amazonica and Pouteria guianensis) in the production of wood-cement composites through a vibro-dynamic compression process, an alternative method to the use of a hydraulic press. The inhibition degree caused by the wood to the cement cure, measured by the factor CA, indicated that all species were compatible with Portland cement (CP II-Z). WCC with densities higher than 1,100 kg m-3 (produced with E. coriaceae and S. recurva particles) showed compressive strength values higher than 10 MPa, which fulfills the minimum requirement for lightweitgh reinforced concrete blocks for structural use.

Cement boards reinforced with wood sawdust: an option for sustainable construction

“…In the present case, this parameter is low when compared to the most tropical species. The main effect of a high extractives content might be the slowing in the curing of the cement as previously pointed out in the introduction by considering the results achieved by Castro et al [13] and the comments of Na et al [29] (Fig. 5).…”

“…Knowledge of the basic density is important since the amount of wood in the board and its final density are influenced by this parameter [13,25,34]. High compaction ratios usually are related to high mechanical strength, but they also can cause drawbacks to other properties, such as hygroscopic swelling of wood in function of hightension rates, originated during the pressing step [21].…”

“…Also, the granulometry of particles affects water absorption, so boards with higher amounts of fiber and fine particles tend to have higher absorption because of their higher specific area [13]. According to Latorraca et al [25] and Iwakiri et al [21] as well, the variation in the granulometry of particles influences the water absorption.…”

“…Depending on the type of extractives present in the raw material, some incompatibility between wood species and the mineral binder can occur. In general, the wood species used for WCB production are conifers, since they usually are more chemically compatible with the cement because they do not have substances that disturb its hardening [13,21]. In contrast, tropical species present the highest levels of incompatibility to the normal hardening of cement, due to both to the quality and concentration of extractives.…”

“…In contrast, tropical species present the highest levels of incompatibility to the normal hardening of cement, due to both to the quality and concentration of extractives. In studies carried out by Castro et al [13], extractive amounts over 15% were determined for tropical wood species. However, as reported by Na et al [29], the non-compatibility of the cement with wood is not only regarded as extractives but also for their chemical nature.…”