Flyash Geopolymer Concrete as Future Concrete

Demand for concrete as construction material is on the increase so as the production of cement. It is estimated that ~6-8% of total CO2 is generated from construction industry. To reduce the concrete industry‟s carbon footprint, blended cements are in use in the market. The research trend is directed towards more eco-friendly concrete such as geopolymer. Recently the focus of research has been shifted on use of fly ash for geopolymerisation. This is based on the alumino-silicate composition of fly ash, it‟s easy availability, better flow ability and improved durability. The chemical composition of geopolymer is similar to that of zeolite, but amorphous in microstructure. Flyash-based geopolymer concrete show excellent short and long-term properties. The properties and uses of geopolymers are being explored in many scientific and industrial disciplines like modern inorganic chemistry, physical chemistry, colloid chemistry, mineralogy, geology, and in all types of engineering process technologies. The current paper presents scope of flyash based geopolymer concrete as future concrete, summarizes and critically analyses the most important research findings

Durability and Mechanical Behavior of Fly Ash-GGBFS Geopolymer Concrete Utilizing Bottom Ash as Fine Aggregate

The mechanical properties and durability parameters such as wet-dry cycles, water sorptivity, efflorescence and acid resistance of geopolymer concrete synthesized from fly ash of three different origins were evaluated. Scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction tests were conducted to examine the microstructure and mineralogical changes. It has been observed that the performance of geopolymer concrete containing fly ash with more glass content was better. The concrete samples were exposed to atmosphere for 180 days under a wide range of temperature (11o to 39oC) and relative humidity (42 to 82%). But the efflorescence was very low and the compressive strength deterioration was <10% from reference sample kept under controlled condition. This indicates good durability characteristic of fly ash based geopolymer concrete

Replacement of conventional fine aggregate with bottom ash in geopolymer concrete

The commonly used fine aggregate in concrete and mortar is river sand. The steep demand of river sand for infrastructure development is faced with problems of availability, its quality and rising cost. Large scale exploitation of sand is becoming a major concern. Conventional fine aggregate for concrete needs replacement for economic, environmental and ecological benefits.To overcome thepresent crisis, an investigation is made by replacingtheriver sand with bottom ash (BA)in geopolymer concrete (GC). The specimens used in the studies of GC issynthesised from fly ash (FA) of three different originsat ambient temperature with alkali activators of different concentrations. Workability and bleeding of fresh concrete are studied. It has been observed that the compressive strength and split tensile strength of third origin of FA based GC was better as compared to first and second origin FA based GC, which can be correlated with higher glass content. Considering the fresh and hardened properties of GC, the BAcontentwas optimisation at 10% of mix proportion

Leaching and efflorescence effects in geopolymer concrete

The leaching behaviour and efflorescence effects were minimal for geopolymer concrete synthesised from fly ash of three different origins have been evaluated. The specimens used in the studies were geopolymer concrete synthesized at ambient temperature with alkali activators of different concentrations. During these studies, extraction and leaching of various heavy metals and trace elements like Zn, Ni, Cu, Fe, Pb, Mn, Mg, and Cd were carried out by applying batch leach test and toxicity characteristic leaching procedure (TCLP) to check the possibility of ground water contamination. The effect of efflorescence was examined visually and by determining the residual compressive strength up to 180 days after 28 days maturity of concrete specimens. The bulk of the pores lie in the 0.01–1.5μm range. The number of pores below pore size of 0.01 μm and above pore size of 1.5 μm is less. 6MFA3GC was better resistant as compared to 6MFA1GC and 6MFA2GC for leaching and efflorescence effect. The strength comparison of geopolymer concrete specimens in laboratory conditions and on exposure to weathering conditions are within 10%

Estimation of geopolymer concrete strength from ultrasonic pulse velocity (UPV) using high power pulser

The objective of this paper is to establish the relationship between the ultrasonic pulse velocity (UPV) and the compressive strength of geopolymer concrete. The specimens used in the studies were geopolymer concrete synthesized at ambient temperature with alkali activators of different concentrations. A high power pulser based equipment Ultra-β™ designed at CSIR-NML, Jamshedpur was used for the UPV measurement and the compressive strength tests were carried out at the concrete age of 1, 7, 28, and 90 days. The result shows that the relationship between UPV and the compressive strength of concrete is significantly influenced by age and alkali activator concentration. The UPV and the compressive strength of concrete increase with age, but the rate of increase varies with alkali activator. The study of hardened concrete at an age of 90 days was considered as the reference. It is found that with the same content of alkali activator, a clear relationship curve can be drawn to describe the UPV and compressive strength of hardened concrete. The standard error in estimating compressive strength from the UPV varies from 1.6MPa to 2.34MPa. This paper highlights the UPV and strength relationship for geopolymer concrete prepared with different concentration of alkali activator

Cloning, overexpression, purification, crystallization and preliminary X-ray diffraction analysis of glyceraldehyde-3-phosphate dehydrogenase from Antheraea mylitta

The cloning, overexpression, purification, crystallization and preliminary X-ray crystallographic analysis of glyceraldehyde-3-phosphate dehydrogenase from A. mylitta are reported

Additional file 25: of Comparative genomics and prediction of conditionally dispensable sequences in legume–infecting Fusarium oxysporum formae speciales facilitates identification of candidate effectors

Disease symptoms and relative abundance of Fom -5190a in infected M. truncatula DZA315 root samples. (a) Disease symptoms of DZA315 plants at 14 days post treatment with Fom-5190a or a control (mock) treatment. (b) Relative Fom-5190a fungal abundance was determined by qRT-PCR expression of Fom-5190a_18S relative to M. truncatula_18S expression in M. truncatula DZA315 root samples harvested at 1, 2, 4 and 7 days post inoculation (dpi). Samples are averages ± SE of 4 biological replicates consisting of pools of 10 seedlings. (TIF 2196 kb