Self compacting concrete (SCC) requires a large quantity of fine materials compared to common concrete. In this work waste glass powder was used to replace (50%) of filler required. Two types of SCC were manufactured, a control SCC type (CTL) using cement and limestone filler and another with glass powder replacing 50% of the filler. Mechanical and durability properties, namely, compressive strength, resistivity, chloride ion penetration, carbonation, capillary water absorption and oxygen permeability were assessed on both SCC types. It could be concluded that waste glass powder can be used successfully in SCC improving chloride penetration and water absorption by capillarity and maintaining strength levels. The potential risk of alkali-silica observed on mortar was mitigated when incorporating glass powder.

Cork powder, the major waste from cork processing industries, is generated from grinding, cutting and finishing operations throughout the industrial cork process. Cork powder has been used mainly as fuel in cork industries. Cork waste ash is usually landfilled but if efficiently used in cement based construction materials it could contribute to sustainability. Strength and durability testing was undergone on mortar with 10 and 20% cement replacement with cork waste ash. Although strength is acceptable for 10% cement replacement with cork ash (5% loss at 90 days, compared to control), most durability properties (tested up to 6 months according to test type) reduced performance probably due to a broader pore structure caused by coarse particles in the ash which tested non pozzolanic. Moreover, cork waste ash does not present the necessary requirements in terms of chemical properties considering several standards. Present work has revealed that this cork waste cannot be used as a pozzolan or as a filler in cement based materials. In fact it is known that chemical composition of biomass ash is highly variable due to moisture variations, ash yield and different genetic types of inorganic matter in biomass and therefore it is important to pinpoint which types of biomass waste are adequate or not to use as cement replacement in construction.

Neste trabalho, cinzas de casca de arroz (RHA) e cinzas de cama de frango (BBA), dois resíduos agrícolas, foram avaliadas para uso como substitutos parciais do cimento para produção de concreto leve. Características físicas e químicas de RHA e BBA foram analisadas. Três tipos semelhantes de concreto leve foram produzidos, um controle em que o ligante era totalmente cimento CEM I (CTL) e dois outros tipos de concreto, com substituição de 10% com RHA e BBA, respectivamente. Todos os tipos de concreto leve foram feitos através do ajuste da quantidade de superplastificante para apresentarem a mesma trabalhabilidade. Propriedades de concreto investigados foram resistência à compressão e à flexão em diferentes idades, a absorção por capilaridade, resistividade e resistência à penetração de íons cloreto (método CTH) e carbonatação acelerada. Os resultados dos testes obtidos para o nível de 10% de de substituição de cimento em concreto leve indicam que, embora a adição de BBA tenha conduzido a desempenho inferior em termos dos testes indicativos de degradação, a RHA levou à melhoria das propriedades mecânicas, especialmente resistência inicial e também resultados relacionados ao envelhecimento acelerado, contribuindo para a construção sustentável.

In this study rice husk ash (RHA) and broiler bed ash from rice husk (BBA), two agricultural waste materials, have been assessed for use as partial cement replacement materials for application in lightweight concrete. Physical and chemical characteristics of RHA and BBA were first analyzed. Three similar types of lightweight concrete were produced, a control type in which the binder was just CEMI cement (CTL) and two other types with 10% cement replacement with, respectively, RHA and BBA. All types of similar lightweight concrete were prepared to present the same workability by adjusting the amount of superplasticizer. Properties of concrete investigated were compressive and flexural strength at different ages, absorption by capillarity, resistivity and resistance to chloride ion penetration (CTH method) and accelerated carbonation. Test results obtained for 10% cement replacement level in lightweight concrete indicate that although the addition of BBA conducted to lower performance in terms of the degradation indicative tests, RHA led to the enhancement of mechanical properties, especially early strength and also fast ageing related results, further contributing to sustainable construction with energy saver lightweight concrete.