scholarly journals The role of aggregate granulation on testing fracture properties of concrete

2021 ◽  
Vol 15 (58) ◽  
pp. 376-385
Author(s):  
Marta Słowik
Keyword(s):  
Fracture Process ◽  
Process Zone ◽  
Concrete Structures ◽  
Cement Matrix ◽  
Hardened Cement ◽  
Professional Literature ◽  
Fracture Properties ◽  
Material Fracture ◽  
Fracture Processes

Concrete is a porous material containing aggregate of different sizes, hardened cement matrix with air pores, microcracks and water. Concrete internal structure is different from that of other engineering materials. Furthermore concrete is described as quazi-brittle material. Fracture processes in it form in a way that does not fit within classical theories. Therefore, to describe failure of concrete structures nonlinear fracture mechanics is often applied with success. Basic concrete parameters, like compressive and tensile strength, and modulus of elasticity, are not enough to analyze fracture processes in concrete structures. Additional fracture properties should be tested, among them fracture energy, complete diagram of stress-deformation under axial tension and the width of fracture process zone. Recognizing and testing fracture parameters is of paramount importance when analysing fracture process in concrete structures. The correct data of material’s properties and the adequate fracture model applied in numerical simulations influence final results. In the paper the findings reported in the professional literature are summarized and obtained results of the own numerical simulation are reported in order to  give a deeper knowledge on the role of aggregate on fracture properties of concrete.

scholarly journals The role of the material fracture properties in the size-effect law of concrete structures

1996 ◽  
Vol 18 (1) ◽  
pp. 40-48
Author(s):  
V. Tran Tu
Keyword(s):  
Size Effect ◽  
Process Zone ◽  
Crack Opening ◽  
Concrete Structures ◽  
Fracture Propagation ◽  
Fracture Properties ◽  
Nominal Strength ◽  
Material Fracture ◽  
General Size

The size effect of the nominal stress at failure in concrete structures is dealt within general. An existence of a rather large fracture process zone in front of crack tip is proved to be the main reason leading to the size effect of the nominal strength. On the basis of the new general size-effect law and numerical results of fracture propagation, a particularly proposed size effect law for beams in bending is developed, in which the role of each material fracture characteristic, especially the shape of the stress - crack opening curve, is elaborated clearly.

An Experimental Study on Acoustic Emission Signals during the Three-Point Bending Fracture Test

2014 ◽  
Vol 1000 ◽  
pp. 281-284 ◽  
Author(s):  
Michal Matysík ◽  
Libor Topolář ◽  
Petr Daněk ◽  
Hana Šimonová ◽  
Tomáš Vymazal ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Fracture Test ◽  
Fracture Properties ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Experimental Tool ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture test of specimens of concrete. Much has been said in literature about the fracture energy of concrete and its importance. Acoustic emission is an experimental tool well suited for monitoring fracture processes. Quantitative acoustic emission techniques were used to measure micro fracture properties. For three different concrete mixtures typical acoustic emission patterns were identified in the acoustic emission records to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviours. The results obtained in the laboratory are useful to understand the various stages of micro-cracking activity during the fracture process in quasi-brittle materials such as concrete and extend them for field applications.

Fracture of Quasi-Brittle Materials like Concrete under Compressive Loading

2008 ◽  
Vol 41-42 ◽  
pp. 207-214 ◽  
Author(s):  
Jan G.M. van Mier ◽  
Dominik Meyer ◽  
Hau Kit Man
Keyword(s):  
Fracture Process ◽  
Compressive Loading ◽  
Material Structure ◽  
Hardened Cement ◽  
Material System ◽  
Confining Stress ◽  
Heterogeneous Structures ◽  
Material Fracture ◽  
Cracking Process ◽  
Structural Scale

Fracture under compression is one of the most commonly studied properties of geomaterials like concrete and rock, in particular since these materials reach their best performance in compression. The fracture process is however rather complex due to the heterogeneous structures of said materials. Over the years fundemental studies of fracture under compression have led to a much improved insight in the details of the fracture process depending on the actual composition of the material. Fracture can be described by means of a 4-stage fracture model, which included as most important aspects pre-peak cracking, which is stable and can be arrested by stiffer and stronger elements in the material structure, and post-peak cracking [1]. The latter macroscopic cracks are basically un-stable and can only be arrested by measures at a structural scale, such as applying confining stress or by using positive geometries. The material structure cannot assist in the arrest of the large energetic cracks other than locally affecting the crack path. In the paper an overview is given of the fracture process in compression. Recently we embarked on studying compressive fracture using a simpler material structure, namely foamed hardened cement paste [2]. Stiff aggregates that are normally included in normal concrete have been left-out; instead a larger than usual quantity of large pores is brought into the material, even up to 80%. Studying fracture processes in this simpler material system ultimately allows for a better understanding of the details of the pre-peak cracking process, which is considered more important than the post-peak process since it defines strength.

Toughening Mechanisms in Quasi-Brittle Materials

1993 ◽  
Vol 115 (3) ◽  
pp. 300-307 ◽  
Author(s):  
S. P. Shah ◽  
C. Ouyang
Keyword(s):  
Fracture Process ◽  
Nonlinear Response ◽  
Large Scale ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Brittle Materials ◽  
Toughening Mechanisms ◽  
Theoretical Approaches ◽  
Cement Based Materials ◽  
Fracture Processes

Fracture processes in cement-based materials are characterized by a large-scale fracture process zone, localization of deformation, and strain softening. Many studies have been conducted to understand the toughening mechanisms of such quasi-brittle materials and to theoretically model their nonlinear response. This paper summarizes two innovative experimental techniques which are being developed at the ACBM Center to better define the fracture process zone in cement-based materials. A brief summary is also given of two types of theoretical approaches which attempt to simulate some of the observed nonlinear fracture response of these materials.

Eight Types of HSC

2011 ◽  
Vol 147 ◽  
pp. 293-297
Author(s):  
Rena C. Yu ◽  
Luis Saucedo ◽  
Gonzalo Ruiz ◽  
Xiao Xin Zhang
Keyword(s):  
High Strength Concrete ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
High Strength ◽  
Fracture Properties ◽  
Strength Concrete ◽  
Mechanical And Fracture Properties

In this paper we report the composition, mechanical and fracture properties of eight types of performance-designed high strength concrete. The influences of compositions on the material’s brittleness are explained through the calculated reference size of the Fracture Process Zone (FPZ).

Elucidation of block boundaries as the dissolution channels in hydrated cement

1978 ◽  
Vol 36 (1) ◽  
pp. 484-485
Author(s):  
N.V. Belov ◽  
U.I. Papiashwili ◽  
B.E. Yudovich
Keyword(s):  
Liquid Phase ◽  
Grain Boundaries ◽  
Benzoyl Peroxide ◽  
Phase Contrast ◽  
Active Role ◽  
Point Of View ◽  
Hardened Cement ◽  
Hydrated Cement ◽  
Hardened Cement Paste

It has been almost universally adopted that dissolution of solids proceeds with development of uniform, continuous frontiers of reaction.However this point of view is doubtful / 1 /. E.g. we have proved the active role of the block (grain) boundaries in the main phases of cement, these boundaries being the areas of hydrate phases' nucleation / 2 /. It has brought to the supposition that the dissolution frontier of cement particles in water is discrete. It seems also probable that the dissolution proceeds through the channels, which serve both for the liquid phase movement and for the drainage of the incongruant solution products. These channels can be appeared along the block boundaries.In order to demonsrate it, we have offered the method of phase-contrast impregnation of the hardened cement paste with the solution of methyl metacrylahe and benzoyl peroxide. The viscosity of this solution is equal to that of water.

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