Rationalizing the impact of aging on fiber–matrix interface and stability of cement-based composites submitted to carbonation at early ages

The objective of this work is to show the effect of carbonation at early stages on fiber–cement composites and impact on hydration, chemical and dimension stability. Carbonation increased the content of CaCO3 polymorphs and consumed Ca(OH)2 and other hydrated calcium phases. Micrographs and energydispersive spectrometry showed the CaCO3 formed is precipitated in the pore structure of the matrix, decreasing diffusion of Si, S, and Al during hydration. Therefore, a refining process of pore sizes is produced, and fiber–matrix interface in carbonated composites was improved, leading to volume stabilization of the composite, as indicated by lower drying shrinkage and lower porosity.Peer reviewe

Evaluation of accelerated carbonation curing in cement-bonded balsa particleboard

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq: 464532/2014-0CNPq: 312151/2016-0Processo FAPESP: 2016/07372-9This study aimed to assess the potential usage of balsa wood to produce cement-bonded particleboards as well as to study the effects of accelerated carbonation on the cement-bonded balsa particleboard. Particleboards were subjected to two different curing conditions, (1) conventional curing: control-curing for 48 h in a climatic chamber, followed by 25 days in a saturated environment (98 +/- 2%) in sealed plastic bags at 23 degrees C, (2) accelerated carbonation-curing for 48 h in a climatic chamber, and then in environment with CO2 (24 h concentration of 15%), followed by 24 days in a saturated environment (98 +/- 2%) in sealed plastic bags at 23 degrees C. After 28 days of curing, the particleboards degree of carbonation was evaluated by TG-DTG and XRD analysis. Thermal, physical and mechanical characterizations were conducted following the recommendations of ASTM-E1530 and DIN: 310, 322, 323 standards, respectively. Accelerated carbonation decreased the portlandite content and increased of calcium carbonate content of the studied particleboards. Thermal properties showed that the particleboards could be used as an insulation material in accordance to European Standard (BS EN 13986). Physical and mechanical properties of the studied materials showed that they are potential building particleboard, because this material satisfied the requirements of ISO 8335 standard