Deterioration Process and Estimation of Durability of Reinforced Concrete Beams in Long-Term Exposure to Marine Environment

Kawahigashi, Tatsuo; Kuzume, Kazuhiro; Miyagawa, Toyoaki

doi:10.2208/jscej.1999.613_71

Cited by 4 publications

(7 citation statements)

References 6 publications

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“…General Conditions Pulse Velocity ft/sec (m/s) Excellent Above 15,000 (4,615) Good 12,000-15,000 (3,690-4,615) Questionable 10,000-12,000 (3,080-3,690) Poor 7,000-10,000 (2,150-3,080) Very Poor Below 7,000 (2,150) • In Figure 7, from a study by Kawahigashi (2001) on ways to improve concrete resistance to degradation by sea water, the data symbols themselves are larger than the precision required here. This reference did not prove useful for this study.…”

Section: Sonic Velocity Measurementmentioning

confidence: 99%

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A Phased Array Approach to Rock Blasting

Gertsch¹,

Baird²

2006

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A series of laboratory-scale simultaneous two-hole shots was performed in a rock simulant (mortar) to record the shock wave interference patterns produced in the material. The purpose of the project as a whole was to evaluate the usefulness of phased array techniques of blast design, using new high-precision delay technology. Despite high-speed photography, however, we were unable to detect the passage of the shock waves through the samples to determine how well they matched the expected interaction geometry. The follow-up mine-scale tests were therefore not conducted. Nevertheless, pattern analysis of the vectors that would be formed by positive interference of the shockwaves from multiple charges in an ideal continuous, homogeneous, isotropic medium indicate the potential for powerful control of blast design, given precise characterization of the target rock mass.

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Section: Sonic Velocity Measurementmentioning

confidence: 99%

“…Table 4. Parameters of the concrete samples used by Kawahigashi (2001). Four preliminary samples were cast in the bottoms of milk cartons in order to measure the sonic velocity of concrete, utilizing QuikCrete brand "Mason Mix" with a volumetric ratio of 3.5 parts mortar mix to one part water at room temperature (Figure 8).…”

Section: Sonic Velocity Measurementmentioning

confidence: 99%

A Phased Array Approach to Rock Blasting

Gertsch¹,

Baird²

2006

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“…The results of the research in this field are described in [21][22][23][24]. Methods for treating recycled aggregates with CO 2 in order to increase the density and reduce the absorbency are also known [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

The Influence of the Environment on the Properties of Hybrid Cement-Based Concrete with Steel and Air-Cooled Slags

Martauz¹,

Václavík

Cvopa³

2021

Crystals

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This article presents the results of research that dealt with the development of non-traditional concrete using a hybrid alkali-activated cement. It is concrete based on by-products from a metallurgical plant that replaced 100% of the natural aggregates. Steel slag (CSS, fraction: 0/8 mm) was used as a filler in combination with air-cooled slag (ACBFS, fraction: 8/16 mm and 16/32 mm). Portland blended cement (CEM II/B-S 42.5N) and H-CEMENT were used as binding components in the development of the concrete mixture designs. Both of these cements were produced by Považská cementáreň, a.s., Ladce. Attention was focused on testing the physical and mechanical properties of the developed concretes in various environments. An aqueous environment was selected as the first environment for the placement of test specimens (cubes with 150 mm edges and prisms with dimensions of 100 × 100 × 400 mm3) according to the ČSN EN 206-1 standard and the outdoor environment (August to October). The determination of the cube strength was made after 7, 28, and 90 days, the determination of the flexural and compressive strength was made at the end of the prisms, and the determination of the dynamic modulus of elasticity was made after 28 days on the prisms. The test results of the test specimens, which were placed in two environments, were compared and it was found that, after 90 days, the outdoor environment caused a decrease in the concrete’s strength characteristics when using Portland blended cement (CEM II/ B-S 42.5N) of about 8%; in contrast, when using H-CEMENT, the concrete’s strength increased by about 14%. The use of H-CEMENT and the addition of PUZZOLANIT in the amount of 30% in combination with CEM II/B-S 42.5N in the amount of 70% reduced the decrease in the strength of the concrete after 90 days by about 3%. The research results confirm the suitability of using H-CEMENT and the addition of PUZZOLANIT for the production of concrete based on steel slag (CSS) and air-cooled slag (ACBFS).

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“…Spacers can potentially compromise the integrity of the concrete cover and its effectiveness to protect embedded reinforcement. Indeed, some field studies have reported correlations between the location of spacers and reinforcement corrosion [6][7][8][9][10], suggesting that spacers contribute to premature deterioration. Yet very little fundamental research has been carried out on this issue.…”

Section: Introductionmentioning

confidence: 99%

Improving bond strength and mass transport properties of spacer-concrete interface with textured spacers

et al. 2021

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Spacers are important devices used in all concrete structures to support reinforcing steel and achieve the required cover. However, spacers induce a weak, porous and microcracked interface that facilitates ingress of aggressive agents. This paper aims to address the problem by developing a method to produce cementitious spacers with a range of small-scale surface textures including grooves, squares, rectangles, hemispheres and pyramids. The textured spacers were cast in Portland cement mortar or concrete, cured up to 28 days, and tested for tensile bond strength, accessible porosity and mass transport properties. The properties were correlated to surface characteristics to establish the effects of texture on spacer-concrete interface. Results show that textured spacers promote mechanical interlocking with concrete, thereby increasing bond strength, resistance against microcracking and pressure-induced flow. The use of certain textures can compensate for the negative effects of spacers, achieving similar bond strength and permeability to monolithic concrete without the interface.

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Deterioration Process and Estimation of Durability of Reinforced Concrete Beams in Long-Term Exposure to Marine Environment

Cited by 4 publications

References 6 publications

A Phased Array Approach to Rock Blasting

A Phased Array Approach to Rock Blasting

The Influence of the Environment on the Properties of Hybrid Cement-Based Concrete with Steel and Air-Cooled Slags

Improving bond strength and mass transport properties of spacer-concrete interface with textured spacers

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