Durability of Bamboo Bio-Concretes Exposed to Natural Aging

In recent years, several studies on the durability of cementitious materials combined with vegetable fibers have been developed. In order to understand the properties of these materials in different environmental conditions, they can be subjected to accelerated aging through several cycles of controlled variations of humidity-temperature, wetting-drying, freezing-thawing. However, analyzes that expose such materials to real conditions of use during their useful life are scarce. As a result, this study analyzed the physical, thermal and mechanical behavior of bamboo bio-concretes produced with different volumes of bio-aggregates, which were exposed to the natural aging of the summer in the city of Rio de Janeiro (Brazil). The cementitious binder was is composed, by mass, of cement (30%), metakaolin (30%) and fly ash (40%). The water-to-cement ratio was as 0.30. The mixtures were produced with bamboo volumetric fraction of 30%; 40% and 50%. After 3 months of natural aging during the Brazilian summer (from December to March), the property determined in the hardened state was the compressive strength. In addition, a visual analysis by photograph was also realize. The results revealed that higher the volumetric fraction, higher the decrease of compressive strength. The visual analysis showed several changes of the external aspect of the bio-concretes.

Use Of Olivine For The Production Of MgO-SiO2 Binders

The potential for using MgO and SiO2, recovered from olivine, was investigated for use as a cementitious binder system. The MgO to SiO2 proportion for the binder was fixed at 1:1. The nature of the hydration products were characterized using a variety of techniques including isothermal calorimetry, XRD, FTIR, and SEM. The primary binding component of the paste was determined to be magnesium silicate hydrate (M-S-H). The recovered silica exhibited faster reactivity compared to commercially available silica fume. Compressive strengths in excess of 20 MPa were obtained using the materials recovered from olivine.

A review on effects of ceramic tile waste as partial replacement of coarse aggregate on geopolymer paver block

Paver blocks are used in many areas like street road and other construction places. Due to rapid infrastructure development the use of cement is increasing. Cement emits large amount of carbon dioxide (CO2) and this leads to global warming. Today researches on waste management lead to an eco-friendly product called geopolymer mortar and concrete. To support the development of pavement construction in the civil engineering industry, a new approach to predicting the performance of the geopolymer paver block (GPB) has been proposed. A huge quantity of ceramic waste is generated during processing, transportation and handling. To reduce this waste disposal, ceramic waste can be used as an alternative material to natural coarse aggregate. Fly ash and Ground Granulated Blast-furnace Slag (GGBS) are activated using alkaline solution such as sodium silicate and sodium hydroxide to get cementitious binder. There are various paper and research works based on natural coarse aggregate replaced by various percentages of other industrial waste material and cement replaced by various percentage of other waste material and it is found that there is increase in strength, durability and reduction in cost and utilization of waste material. Various waste material can be used for improving strength of paver block. The primary objective of this review is to understand the properties as well as economical and environmental benefits of GPB using ceramic tile waste corresponding to M40 grade (16M) based on earlier researches. From the mix designed, 25% Fly ash and 75% GGBS shows optimum mix. The review work also focus on selection of various percentages of ceramic tile waste for replacing natural coarse aggregate. Key Words: Geopolymer Paver Block, Fly Ash, GGBS, Cementitious binder, Alkaline solution, Ceramic tile waste