Utilization of Coal Fly ash and ultra fine additives in producing HPC: Influence on early strength, flexural parameters and microstructure
| Autor: | T. Shamanth Gowda, R. V. Ranganath |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science 02 engineering and technology General Medicine 021001 nanoscience & nanotechnology Microstructure 01 natural sciences law.invention Portland cement Compressive strength Flexural strength law Fly ash 0103 physical sciences Ultimate tensile strength Ultra fine Composite material 0210 nano-technology Curing (chemistry) |
| Zdroj: | Materials Today: Proceedings. 32:677-685 |
| ISSN: | 2214-7853 |
| Popis: | This study investigates the beneficial utilization of Coal Fly ash (Class F) in conjunction with certain ultra-fine additives rich in reactive calcium and silica to produce High Performance Concrete (HPC). High early strength, improvement in flexural parameters including flexural toughness and micro structure modifications are considered as key attributes of resulting HPC. Combinations of mineral admixtures are worked out for optimal quantities by limiting Ordinary Portland Cement (OPC) to 450 kg/m3 in concrete. Conventional method of concrete preparation is adopted to make the process of HPC production more realistic and site friendly without depending on high energy intensive High-speed mixers and special curing techniques. Compressive strength is tracked right after 14th hour of concrete casting and up to 56 days. Certain selected mixes are further tested for Flexure performance, Tensile strength, Shear strength, Water permeability and Micro structural characteristics. The results indicate the possibility of enhancing strength up to a highest of 32 MPa and 51 MPa for 14 h and 24 h of concrete casting respectively in case of optimum mixes. Combinations of selected mineral additives have resulted in Ultimate strength of greater than 100 MPa after 28 days of curing which has further improved to a maximum of 127 MPa as on 56th day. Flexural strength has shown a comparative improvement by 19–26% from reference with considerable improvement in Flexural toughness. For best performing mixes resistance to tensile stresses and shearing stresses is recorded to be enhanced by 29% and 27% respectively. Concrete compactness is analysed by measuring resistance to water ingress under pressure along with Microscopic studies to understand modifications in the concrete microstructure. |
| Databáze: | OpenAIRE |
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