Use of Cactus Wood Cereus Jamacaru as Aggregate in Lightweight Bioconcrete Production

Abstract

It is constant, especially in the civil construction sector, the search for new material sources that meet the assumptions of sustainable development. In this way, the cacti are pointed as a good alternative. Therefore, the objective of the present research was to develop and characterize physically and mechanically lightweight bioconcretes produced with Cereus wood from this lignocellulosic source. Cereus jamacaru wood was used after washing in hot water (at 80° C). In the studied matrix, Portland Cement CP V-ARI was used and a water-to-cement ratio of 0.4. To accelerate the cement hydration reactions 3% (relative to the cement mass) of calcium chloride was added. Mixtures with two types of wood particles classified as green and brown were produced and for both cases varying the percentage of compensation water (100 and 200%), cement-to-wood ratio (3,4 and 7) and moulding method (compacting with metal rod or not). A flow table test was used to characterize the fresh mixtures. The mechanical characterization was performed through uniaxial compression test. The density of the composites with the brown particles varied from 892 to 1452 kg/m³ and the compressive strength from 3.38 to 10.51 MPa. The blends with green particles reached between 872 and 1347 kg/m³ of density and between 1.72 and 8.94 MPa of compressive strength. The mixtures with higher cement-to-wood proportions and lower amount of compensating water reached higher compressive strength. The results show that Cactus Wood can be used in the production of bioconcretes with good properties and varied applications in civil construction.

Efeito de diferentes espécies de madeira e bambu na hidratação de matrizes à base de cimento Portland

“…Estas espécies foram escolhidas, pois segundo ZHOU e KAMDEM [19], sua presença é responsável pelo menor custo dos painéis. O produto final possui ainda, na maioria das vezes, maior leveza, visto que a densidade das espécies de Pinus taeda (0,32 g/cm 3 ) [20], Bambusa vulgaris (0,73 g/cm 3 ) [21] e Cereus jamacaru (0,25 g/cm 3 ) [22], é menor que a do cimento (Tabela 1). Além disso, tais espécies possuem grande disponibilidade no território brasileiro [12].…”

“…Tal fato se dá pela idade da árvore abatida [28 anos], a maior dentre as espécies pesquisadas, pois segundo MAGALHÃES et al [41], a madeira adulta apresenta maior permeabilidade do que a madeira jovem, e também pela sua alta quantidade de lignina. A amostra de Cereus jamacaru após o processo de lavagem, porém, apresentou os maiores percentuais de absorção de água (850,00%) e umidade (134,25%), decorrentes, possivelmente, da baixa idade da espécie extraída (3 anos), pelo baixo conteúdo de lignina encontrado, o menor dentre as espécies estudadas e também pela grande presença de vazios nesta espécie [22,41].…”