Influence of the micro- and nanoscale local mechanical properties of the interfacial transition zone on impact behavior of concrete made with different aggregates

Erdem, Savaş; Dawson, Andrew; Thom, Nick

doi:10.1016/j.cemconres.2011.11.015

Cited by 116 publications

(26 citation statements)

References 20 publications

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“…Compared with cement paste, it is porous and of low stiffness and strength (Diamond 1992a(Diamond , 1992bOliver et al 1995;Sonebi 2006;Erdem et al 2012). In general use, the term ITZ includes both the pores on the aggregate surface and the coarser paste or mortar matrix around the aggregate rather than the matrix located far from the surface of aggregate.…”

Section: Model Analysis Considering Itzmentioning

confidence: 99%

Numerical Study on Drying Shrinkage of Concrete Affected by Aggregate Size

Maruyama

Sugie

2014

ACT

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This paper describes new insights on the influence of aggregate size on drying shrinkage of concrete through numerical simulation. Using a two-dimensional finite element method, it is demonstrated that it is impossible to reproduce the impact of aggregate size on concrete drying shrinkage by simply considering crack opening in the mortar matrix. From this result, it is deduced that the effect of aggregate size on concrete shrinkage is influenced by aggregate surface area. The application of a constitutive law that considers the characteristics of ITZ to coarse aggregate elements successfully reproduced the damage and shrinkage strain of concretes with different aggregate sizes. A certain range of virtual ITZ pore thickness in the model was found to allow simulation of the real phenomenon. It is concluded that ITZ characteristics should be taken into account when considering aggregate behavior in drying concrete.

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Section: Model Analysis Considering Itzmentioning

confidence: 99%

Numerical Study on Drying Shrinkage of Concrete Affected by Aggregate Size

Maruyama

Sugie

2014

ACT

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“…Due to the lower strength and stiffness of the interphase region, the first microcracks resulting from mechanical loads will appear in this region and will impact the overall mixture behavior [1][2][3]. Many studies, by using scanning electron microscopy (SEM), have identified the microstructural characteristics of the interphase region in concrete and shown that ITZ is extremely heterogeneous and distinct from the surrounding paste [2,[4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

An integrated microstructural-nanomechanical-chemical approach to examine material-specific characteristics of cementitious interphase regions

Khedmati

Kim

Turner

et al. 2018

Materials Characterization

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Abstract:Effective properties and structural performance of cementitious mixtures are substantially governed by the quality of the interphase region because it acts as a bridge transferring forces between aggregates and a binding matrix and is generally susceptible to damage. As alternative binding agents like alkali-activated precursors have obtained substantial attention in recent years, there is a growing need for fundamental knowledge to uncover interphase formation ACCEPTED MANUSCRIPTA C C E P T E D M A N U S C R I P T mechanisms. In this paper, two different types of binding materials, i.e., fly ash-based geopolymer and ordinary portland cement, were mixed with limestone aggregate to examine and compare the microstructures and nanomechanical properties of interphase region. To this end, microstructural characteristics using scanning microscopies, nanomechanical properties by nanoindentation tests, and spatial mapping of chemical contents based on the energy dispersive spectroscopy were integrated to identify and investigate the interphase region formed by the case-specific interactions between the matrix materials and limestone. The integrated microstructural-nanomechanicalchemical approach was effective to better understand links between material-specific properties of cementing phases. More specifically, the fly ash-based geopolymer paste was usually well bonded to the aggregate surface with a rich formation of N-A-S-H gel, while interfacial debonding was often observed between aggregate surface and paste in ordinary portland cement concrete. However, when a good bonding between aggregate and paste is formed, interphase region in PCC didn't show any considerable difference in nanomechanical properties compared to the bulk paste. ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T An Integrated Microstructural-Nanomechanical-Chemical Approach to Examine MaterialSpecific Characteristics of Cementitious Interphase Regions Abstract:Effective properties and structural performance of cementitious mixtures are substantially governed by the quality of the interphase region because it acts as a bridge transferring forces between aggregates and a binding matrix and is generally susceptible to damage. As alternative binding agents like alkali-activated precursors have obtained substantial attention in recent years, there is a growing need for fundamental knowledge to uncover interphase formation mechanisms. In this paper, two different types of binding materials, i.e., fly ash-based geopolymer and ordinary portland cement, were mixed with limestone aggregate to examine and compare the microstructures and nanomechanical properties of interphase region. To this end, microstructural characteristics using scanning microscopies, nanomechanical properties by nanoindentation tests, and spatial mapping of chemical contents based on the energy dispersive spectroscopy were integrated to identify and investigate the interphase region formed by the case-specific interactions between the matrix materials and limestone. The...

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“…Very interesting results and findings regarding the problem of the interfacial transition zone between aggregates and matrix are stated in studies [22] to [24]. These studies present both current knowledge and new progressive methods, however porous aggregate or particularly agloporite are not investigated.…”

Section: Recommendation For Consequential Researchmentioning

confidence: 83%