Crack widths in ASTM C-1550 panels

Shotcrete ◽  
2010 ◽  
pp. 21-28 ◽  
Author(s):  
E Bernard ◽  
G Xu
Keyword(s):  
Crack Widths

Evaluation of the expansion attained to date by concrete affected by alkali–silica reaction. Part III: Application to existing structures

2005 ◽  
Vol 32 (3) ◽  
pp. 463-479 ◽  
Author(s):  
Marc-André Bérubé ◽  
Nizar Smaoui ◽  
Benoit Fournier ◽  
Benoit Bissonnette ◽  
Benoit Durand
Keyword(s):  
Prestressed Concrete ◽  
Alkali Silica Reaction ◽  
Existing Structures ◽  
Concrete Members ◽  
Crack Widths ◽  
Concrete Petrography ◽  
Made In

The expansion attained by a concrete affected by alkali-silica reaction (ASR) is an important parameter in the evaluation of the corresponding structure. In part I, relationships were established in the laboratory between the ASR expansion and the stiffness damage test (SDT), the damage rating index (DRI), and the cumulated width of cracks observed at the surface of concrete specimens made with various types of reactive aggregates. In part II, these relationships were verified in the case of specimens made in laboratory but exposed outdoors. In part III, the aforementioned methods were applied to three ASR-affected structures. The measurement of crack widths at the surface of the affected members allowed a rather good estimation of the concrete expansion, provided the measurements were taken on the most severely exposed sections of these members. The DRI did not allow differentiating the most visually and mechanically affected concretes from the least affected concretes. The SDT proved to be the most interesting method to date for evaluating the expansion of ASR-affected concrete; however, it seemed to underestimate the expansion of the prestressed concrete members investigated.Key words: aggregates, alkali–silica reaction, concrete, petrography, expansion, stiffness, cracking.

Self healing properties with various crack widths under continuous water leakage

2008 ◽  
pp. 121-122 ◽  
Author(s):  
T Kishi ◽  
K Kobayashi ◽  
S Komatsu ◽  
A Hosoda ◽  
S Ikeno ◽  
...  
Keyword(s):  
Self Healing ◽  
Water Leakage ◽  
Crack Widths

scholarly journals Mechanical-Damage Behavior of Mortars Reinforced with Recycled Polypropylene Fibers

2019 ◽  
Vol 11 (8) ◽  
pp. 2200 ◽  
Author(s):  
Gerardo Araya-Letelier ◽  
Pablo Maturana ◽  
Miguel Carrasco ◽  
Federico Carlos Antico ◽  
María Soledad Gómez
Keyword(s):  
Flexural Strength ◽  
Impact Resistance ◽  
Mechanical Damage ◽  
Physical And Mechanical Properties ◽  
Experimental Program ◽  
Polypropylene Fibers ◽  
Recycled Polypropylene ◽  
Formation Of Cracks ◽  
Crack Widths

Commercial polypropylene fibers are incorporated as reinforcement of cement-based materials to improve their mechanical and damage performances related to properties such as tensile and flexural strength, toughness, spalling and impact resistance, delay formation of cracks and reducing crack widths. Yet, the production of these polypropylene fibers generates economic costs and environmental impacts and, therefore, the use of alternative and more sustainable fibers has become more popular in the research materials community. This paper addresses the characterization of recycled polypropylene fibers (RPFs) obtained from discarded domestic plastic sweeps, whose morphological, physical and mechanical properties are provided in order to assess their implementation as fiber-reinforcement in cement-based mortars. An experimental program addressing the incorporation of RPFs on the mechanical-damage performance of mortars, including a sensitivity analysis on the volumes and lengths of fiber, is developed. Using analysis of variance, this paper shows that RPFs statistically enhance flexural toughness and impact strength for high dosages and long fiber lengths. On the contrary, the latter properties are not statistically modified by the incorporation of low dosages and short lengths of RPFs, but still in these cases the incorporation of RPFs in mortars have the positive environmental impact of waste encapsulation. In the case of average compressive and flexural strength of mortars, these properties are not statistically modified when adding RPFs.

Methods of Evaluating the Performance of Fiber-Reinforced Concrete

1990 ◽  
Vol 211 ◽  
Author(s):  
Colin D. Johnston
Keyword(s):  
Reinforced Concrete ◽  
Fiber Reinforced Concrete ◽  
Material Behavior ◽  
Fiber Reinforced ◽  
Thermal Change ◽  
Advantages And Disadvantages ◽  
Concrete Quality ◽  
Predetermined Level ◽  
Loading Tests ◽  
Crack Widths

AbstractThree of the most important properties of fiber-reinforced concrete (FRC) are strength, toughness and resistance to cracking. The various methods of evaluating them are compared in terms of underlying rationale, ability to characterize composite material behavior in a readily understandable manner minimally affected by testing variables, and suitability for routine use in specifying and controlling concrete quality. The scope includes dynamic loading tests, slow-rate (static) loading tests, and tests to evaluate cracking induced directly by load or indirectly by restraint during shrinkage or thermal change.Consideration of the advantages and disadvantages of the various alternatives shows that slow flexure testing in accordance with the rationale developed by the writer and incorporated into ASTM standard C1018 effectively characterizes the FRC in terms of first-crack strength, toughness, and residual strength after first crack up to any predetermined level of serviceability expressed in terms of maximum permissible deflection. Although not part of the standard, resistance to cracking under load may also be assessed by measuring crack widths at appropriate deflections.

The first 7 years (1978–1985) of ice wedge growth, Illisarvik experimental drained lake site, western Arctic coast

1986 ◽  
Vol 23 (11) ◽  
pp. 1782-1795 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
Growth Rates ◽  
Linear Expansion ◽  
Temperature Dependent ◽  
Frozen Ground ◽  
Ice Wedge ◽  
Western Arctic ◽  
Arctic Coast ◽  
Coefficient Of Linear Expansion ◽  
Lake Site ◽  
Crack Widths

A large lake, measuring 600 m × 300 m and with a depth of nearly 5 m, was artificially drained on 13 August 1978. Observations on the formation, width, and depth of thermal contraction cracks for the first 7 years show that the crack profiles and ice wedge growth rates differ markedly from those of old ice wedges reported in the literature. The first winter's cracks had box-like profiles, with surface widths to 10 cm and depths to 2.5 m. Some cracks continued to widen and deepen, once opened in early winter, and then narrowed or even closed completely in summer. Mean growth rates for the ice wedges for the first few years have been as much as 3.5 cm/year. Temperature gradients at the time of first cracking have been in the range of 10–15 °C/m. The growth rate of young ice wedges is site specific and temperature dependent, varying with factors such as the temperature gradient, vegetation, and snow cover, so an estimate of the age of an ice wedge from its width will usually be impossible. A study of crack widths indicates that the apparent coefficient of linear expansion of frozen ground may be several times that of ice. Upward cracking has been proven.

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