Experimental Study on Effects of Casting Procedures on Compressive Strength, Water Permeability, and Interfacial Transition Zone Porosity of Rock-Filled Concrete

2016 ◽  
Vol 28 (8) ◽  
pp. 04016055 ◽  
Author(s):  
Yiyang Wang ◽  
Feng Jin ◽  
Yuetao Xie
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Transition Zone ◽  
Water Permeability ◽  
Interfacial Transition Zone

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.

Experimental Study of Diffusivity of the Interfacial Transition Zone between Cement Paste and Aggregate

2016 ◽  
Vol 28 (10) ◽  
pp. 04016109 ◽  
Author(s):  
Zhilu Jiang ◽  
Qinghua Huang ◽  
Yunping Xi ◽  
Xianglin Gu ◽  
Weiping Zhang
Keyword(s):  
Experimental Study ◽  
Transition Zone ◽  
Cement Paste ◽  
Interfacial Transition Zone

The Interfacial Transition Zone: “Direct” Evidence on Compressive Response

1994 ◽  
Vol 370 ◽  
Author(s):  
David Darwin
Keyword(s):  
Compressive Strength ◽  
Transition Zone ◽  
Cement Paste ◽  
Direct Evidence ◽  
Indirect Evidence ◽  
Interfacial Strength ◽  
Interfacial Transition Zone ◽  
Compressive Response ◽  
Heterogeneous Nature ◽  
Compressive Strength Of Concrete

AbstractThere is little question that the strength of the interfacial transition zone (MTZ) between cement paste and aggregate affects the compressive strength of concrete. The key question, rather, is to what degree? It is difficult to directly measure the response of the overall composite to changes in interfacial properties, since it is difficult to isolate interfacial strength as the only variable.Research on the effects of interfacial strength on the compressive response of concrete that comes the closest to providing direct evidence is summarized. The studies, dating to the 1950's, include both experimental and analytical efforts aimed at isolating the effects of the ITZ, as well as experimental efforts that are considered to provide strong indirect evidence. The research shows that the ITZ plays a measurable role in the response of concrete to compressive stress, but that its role is overshadowed by the properties of the cement paste and aggregate constituents of concrete and the heterogeneous nature of the composite.

scholarly journals A Micromechanics-Based Model for Stiffness and Strength Estimation of Cocciopesto Mortars

10.14311/1672 ◽  
2012 ◽  
Vol 52 (6) ◽  
Author(s):  
Václav Nežerka ◽  
Jan Zeman
Keyword(s):  
Compressive Strength ◽  
Transition Zone ◽  
Experimental Validation ◽  
Interfacial Transition Zone ◽  
Effective Stiffness ◽  
Geometrical Meaning ◽  
Gel Layer ◽  
Quadratic Invariants ◽  
Parametric Studies ◽  
Deviatoric Stresses

The purpose of this paper is to propose an inexpensive micromechanics-based scheme for stiffness homogenization and strength estimation of mortars containing crushed bricks, known as cocciopesto. The model utilizes the Mori-Tanaka method for determining the effective stiffness, combined with estimates of quadratic invariants of the deviatoric stresses inside phases to predict the compressive strength. Special attention is paid to the representation of the C-S-H gel layer around bricks and the interfacial transition zone around sand aggregates, which renders the predictions sensitive to particlesizes. Several parametric studies are performed to demonstrate that the method correctly reproduces the data and trends reported in the available literature. Moreover, the model is based exclusively on parameters with a clear physical or geometrical meaning, and as such it provides a convenient framework for its further experimental validation.

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