Mesomechanical creep model of fly ash-contained cement mortar considering the interfacial transition zone and its influential factors

2021 ◽  
Vol 308 ◽  
pp. 124985
Author(s):  
Zehua Xu ◽  
Qingxin Zhao ◽  
Weichao Guo ◽  
Jinrui Zhang ◽  
Jiannan Tong
Keyword(s):  
Fly Ash ◽  
Transition Zone ◽  
Cement Mortar ◽  
Influential Factors ◽  
Interfacial Transition Zone ◽  
Creep Model

scholarly journals Experimental study on the compressive strength, damping and interfacial transition zone properties of modified recycled aggregate concrete

2019 ◽  
Vol 6 (12) ◽  
pp. 190813
Author(s):  
Bin Lei ◽  
Huajian Liu ◽  
Zhimin Yao ◽  
Zhuo Tang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Transition Zone ◽  
Loss Factor ◽  
Steel Fibre ◽  
Interfacial Transition Zone ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Damping Properties ◽  
Aggregate Concrete

At present, many modification methods have been proposed to improve the performance of recycled aggregate concrete (RAC). In this study, tests on the compressive strength and damping properties of modified RAC with the addition of different proportions of recycled coarse aggregate (RCA) (0, 50, 100%), rubber powder (10, 15, 20%), steel fibre (5, 7.5, 10%) and fly ash (15, 20, 5%) are carried out. To elucidate the effect of the modification method on the interfacial transition zone (ITZ) performance of RAC, model ITZ specimens are used for push-out tests. The results show that when the replacement rate of RCA reaches 100%, the loss factor of the RAC is 6.0% higher than that of natural aggregate concrete; however, the compressive strength of the RAC decreases by 22.6%. With the addition of 20% rubber powder, the damping capacity of the modified RAC increases by 213.7%, while the compressive strength of the modified RAC decreases by 47.5%. However, with the addition of steel fibre and fly ash, both the compressive strength and loss factor of the RAC specimens increase. With a steel fibre content of 10 wt%, the compressive strength and loss factor of the RAC increase by 21.9% and 15.2%, respectively. With a fly ash content of 25 wt%, the compressive strength and loss factor of the RAC increase by 8.6% and 6.9%, respectively. This demonstrates that steel fibre and fly ash are effective in improving both the damping properties and compressive strength of RAC, and steel fibre is more effective than fly ash. Two methods were used for modification of the RAC: reinforcing the RCA through impregnation with a 0.5% polyvinyl alcohol (PVA) emulsion and nano-SiO 2 solution, and strengthening the RAC integrally through the addition of fly ash as an admixture. Both of these techniques can improve the ITZ bond strength between the RAC and new mortar. Replacing 10% of the cement with fly ash in the new mortar is shown to be the best method to improve the ITZ strength.

scholarly journals Influence of Graphene Oxide on Interfacial Transition Zone of Mortar

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Hongfang Sun ◽  
Zhili Ren ◽  
Li Ling ◽  
Shazim Ali Memon ◽  
Jie Ren ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Image Analysis ◽  
Graphene Oxide ◽  
Prediction Model ◽  
Transition Zone ◽  
Cement Mortar ◽  
Interfacial Transition Zone ◽  
Backscattered Electron ◽  
The Difference

In this paper, the influence of graphene oxide (GO) on the microstructure of interfacial transition zone (ITZ) in cement mortar was investigated through image analysis (IA) of backscattered electron (BSE) micrographs. The results showed that the incorporation of GO significantly reduced the thickness of ITZ. The porosity in ITZ and bulk paste decreased due to the introduction of GO; meanwhile, the compressive strength of the mortar samples was improved. The addition of GO also narrowed the gap between the porosity of ITZ and bulk paste, and therefore, the entire microstructure of mortar became more homogenous. Based on the above results, the model to predict the compressive strength of mortar was modified for better precision. The improved prediction model indicated that the difference between the compressive strength of ITZ and bulk paste was reduced upon the refinement of ITZ by GO.

Increase of bond strength at interfacial transition zone by the use of fly ash

2000 ◽  
Vol 30 (2) ◽  
pp. 253-258 ◽  
Author(s):  
Masao Kuroda ◽  
Tomohide Watanabe ◽  
Nariaki Terashi
Keyword(s):  
Fly Ash ◽  
Bond Strength ◽  
Transition Zone ◽  
Interfacial Transition Zone

scholarly journals The Application of Berkovich nanoindenter to the study of interfacial transition zone in concretes containing fly-ash

2014 ◽  
Vol 13 (2) ◽  
pp. 085-092
Author(s):  
Grzegorz Golewski
Keyword(s):  
Fly Ash ◽  
Grain Boundary ◽  
Transition Zone ◽  
Interfacial Transition Zone ◽  
Berkovich Indenter ◽  
Fly Ashes ◽  
Transition Zones ◽  
Coarse Aggregates ◽  
Percent Increase ◽  
Technique Analysis

The paper presents the results of nanohardness (HB) in the Interfacial Transition Zones (ITZ) of concretes with the addition of 0, 20 and 30% siliceous fly ashes (FA). A compact platform CSM Instruments was used in the testing. An area in the ITZ of coarse aggregates with paste was analysed in the five measurement points during the experiments, i.e. at the distance of: 5, 25, 50, 100 and 150 µm from the grain boundary. The indents in concrete were create by Berkovich indenter using DSI technique. Analysis of the results revealed that the 20% additive of FA causes a few percent increase in nanohardness, while 30% FA additive leads to between ten and twenty percent drop of HB. On the basis of nanohardness distributions in particular concretes, it was found that the most heterogeneous one is the ITZ zone within the distance of 25µm from the aggregate grain.

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