International Concrete Abstracts Portal

International Concrete Abstracts Portal

The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

Showing 1-5 of 14 Abstracts search results

Document: 

SP118-07

Date: 

January 1, 1990

Author(s):

Arne Hillerborg

Publication:

Symposium Papers

Volume:

118

Abstract:

A fracture mechanics approach is presented. In this approach, the complete material behavior during tensile fracture is described in a way suitable for the analysis of failure of structures. Two examples are given of practical applications, in which the results can be compared with code specifications. The first is the cracking strength of a beam. It is demonstrated that the formal flexural stress that causes cracking decreases as the depth of the beam increases. The second example is the shear strength of a beam without shear reinforcement. The theoretical results show a good agreement with test results. There seem to be reasons to revise the rules in the ACI Building Code regarding the influence of beam depth, of span-to-depth ratio, and of the amount of longitudinal reinforcement on the shear strength. The tensile toughness of concrete, expressed as fracture energy, proves to be an important material property, which ought to be taken into account.

DOI:

10.14359/2947


Document: 

SP118-08

Date: 

January 1, 1990

Author(s):

Zdenek P. Bazant, Siddik Sener, and Pere C. Prat

Publication:

Symposium Papers

Volume:

118

Abstract:

This symposium contribution gives a preliminary report on tests of the size effect in torsional failure of plain and longitudinally reinforced beams of reduced scale, made of microconcrete. The results confirm that there is a significant size effect, such that the nominal stress at failure decreases as the beam size increases. This is found for both plain and longitudinally reinforced beams. The results are consistent with the recently proposed Bazants size effect law. However, the scatter of the results and the scope and range limitations prevent it from concluding that the applicability of this law has been proven in general.

DOI:

10.14359/2955


Document: 

SP118-01

Date: 

January 1, 1990

Author(s):

Victor c. Li

Publication:

Symposium Papers

Volume:

118

Abstract:

Reviews the tensile failure of concrete structures subjected to a variety of practical loading. Attention is focused on the propensity of fracture failure of concrete structures and the fracture properties of cementitious materials. The relevance of fracture mechanics to modern concrete design code is highlighted.

DOI:

10.14359/2908


Document: 

SP118-02

Date: 

January 1, 1990

Author(s):

R. J. Ward, K. Yamanobe, V. C. Li, and S. Backer

Publication:

Symposium Papers

Volume:

118

Abstract:

Results of notched beam, direct tension, splitting tension, compression, shear beam, and flexural tests on plain mortar and on mortar reinforced with different volume fractions of short acrylic fibers are reported. An indirect J-integral technique is employed to determine the tension-softening curve and thus the tensile strength, the fracture energy, and the critical crack opening from the notched beam test results. As the volume fraction of fibers is increased, the strength in shear and flexure, the fracture energy, and the critical crack opening all increase, the tensile strength remains essentially constant, and the compressive strength shows some reduction. The characteristic length lch is used as a material property to characterize the post-peak tensile behavior. The shear and flexural strengths are related to the normalized dimension d/lch, and good agreement between the experimental results and theoretical predictions of decreasing strength with increasing d/lch is found.

DOI:

10.14359/2878


Document: 

SP118-03

Date: 

January 1, 1990

Author(s):

C. Vipulanandan and N. Dharmandan

Publication:

Symposium Papers

Volume:

118

Abstract:

Fracture behavior of epoxy and polyester polymer concrete (PC) systems are investigated in Mode I fracture using single-edge notched beams with varying notch depths. The beams were loaded in four-point bending. Influence of polymer content on the fracture behavior of epoxy PC andpolyester PC at room temperature was studied using uniform Ottawa 20-30 sand. The polymer content was varied between 10 and 18 percent of the total weight of the composite. The flexural strength of the polymer concrete systems increase with increase in polymer content while the flexural modulus goes through a maximum. The critical stress intensity factor KIC was determined by two methods, including a method based on crack mouth opening displacement. At the same polymer content, the epoxy PC has a higher fracture toughness than polyester PC. The KIC for epoxy PC and polyester PC increases with increase in polymer content and PC flexural strength. The critical stress intensity factor of PC is represented in terms of polymer content and polymer strength. Numerical tests based on random sampling and stratified sampling procedures were performed to substantiate the experimentally observed fracture toughness values of polymer concrete.

DOI:

10.14359/2921


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