Szerző szerinti böngészés "Thankam, G. Lizia"

Megjelenítve 1 - 2 (Összesen 2)
  • Nincs kép
    TételSzabadon hozzáférhető
    Effect of ultrafine natural steatite powder, super plasticizer and VMA on the fresh and hardened properties of self-compacting cement paste and mortar
    (Akadémiai Kiadó, 2021-12) Gnanaraj, S. Christopher; Chokkalingam, Ramesh Babu; Thankam, G. Lizia; Pothinathan, S.K.M.; nem
    For the past few decades innovation in construction material has grown a lot. This leads to special concrete such as self-compacting concrete, geopolymer concrete, self-healing concrete, etc. To prepare a special concrete apart from regular concreting material some sort of special materials was also needed, like mineral and chemical admixtures. Hence it is necessary to study the effect of these admixtures in cement paste and mortar before studying the same in concrete. Hence an attempt is made to study the effect of mineral and chemical admixtures in the fresh and hardened properties of cement paste and mortar. For this study ultrafine natural steatite powder is taken as mineral admixture and polycarboxylic based superplasticizer and glenium stream 2 were taken as chemical admixtures. Ultrafine natural steatite powder was used as additive to cement in various percentages like 0%, 5%, 10%, 15%, 20% and 25%. Superplasticizer and viscosity modifying admixture were taken as 1.5% and 0.5%, respectively. Then various combinations were worked out. To study the fresh property of cement paste consistency, initial setting time and miniature slump cone test were done based on the results yield stress of cement paste also calculated empirically. To study the hardened property compression test on cement mortar was done. Based on the test results it is clear that the addition of ultrafine natural steatite powder increases the water demand hence reduces the workability. On the other hand, it increases the compressive strength up to a certain limit. Adding superplasticizer increases the workability and reduces the water demand and viscosity modifying admixture reduces the bleeding and segregation effects hence increases the compressive strength.
  • Nincs kép
    TételSzabadon hozzáférhető
    GGBS based alkali activated fine aggregate in concrete - Properties at fresh and hardened state
    (Akadémiai Kiadó, 2021-10-13) Thankam, G. Lizia; Neelakantan, T.R.; Gnanaraj, S. Christopher; nem
    Scarcity of the construction materials, peculiarly the natural river sand has become a serious threat in the construction industry. Though many researchers of developed and developing countries are trying to find alternative sources for the same, the complete replacement of the fine aggregate in concrete is crucial. Geopolymer sand developed from the Industrial waste (Ground granulated blast furnace slag - GGBS) is an effective alternative for the complete replacement of the natural sand. The GGBS based geopolymer sand (G-GFA) was tested for physical and chemical properties. Upon the successful achievement of the properties in par with the natural river sand, the fresh properties (fresh concrete density & slump) and hardened properties (compressive strength, tensile strength & flexural strength) of the concrete specimens developed with G-GFA were studied. The G-GFA is obtained by both air drying (AD-G-GFA) and oven drying (OD-F-GFA) after the dry mixing of the alkaline solution and GGBS for about 10 min. Thus, developed fine aggregates were studied separately for the fresh and hardened concrete to optimize the feasible one. Superplasticizer of 0.4% is included in the concrete mix to compensate the sightly hydrophilic nature of the fine aggregates produced. The mechanical properties of the concrete with G-GFA are observed to be more than 90% close to that of the concrete developed with natural river sand. Thus, both the fresh and mechanical properties of the G-GFA concrete specimens resulted in findings similar to those of the control specimen developed with natural river sand reflecting the plausibility of G-GFA as a complete replacement choice to the fine aggregate in the concrete industry. The flaky GGBS particles merge well with the alkaline solution at room temperature itself since the former gets dried at elevated temperatures. Thus, more feasible fresh concrete properties and mechanical properties were recorded for the AD-G-GFA than the OD-G-GFA.