EXAMINATION OF FROST DAMAGE RESISTANCE FOR FREEZE-THAW OF LIGHTWEIGHT CONCRETE TYPE 2

Freezing-thawing durability of cement concrete is extremely important in cold weather, to better understand mechanism of frost damage and air-entraining，saturation degree of pores in concrete and its relation with frost resistance were studied in this paper. Concrete specimens with different saturation degree from 0 to 100% were prepared used a sealed tin with a high water pressure pump. Then these specimens were subjected to six freezing-thawing cycles and the relative dynamic modulus of elasticity was examined. The results showed that critical saturation degree of concrete with water- binder ratio of 0.30 and 0.47, air content of 1%, 4% and 6% were from 0.60 to 0.80. When its saturation degree exceeded the critical value, concrete was deteriorated significantly after only six freeze-thaw cycles. The critical saturation degree was mainly related to the air content of concrete mixture, and it decreased with the increasing of air content. The difference between the saturation degree and the critical value can be used to evaluate potential frost resistance of concrete, and its result was consistent with the result of frost tests very well.

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Effects of Cyclic Freeze–Thaw on the Steel Bar Reinforced New-To-Old Concrete Interface

Molecules ◽

10.3390/molecules25051251 ◽

2020 ◽

Vol 25 (5) ◽

pp. 1251

Author(s):

Tao Luo ◽

Chi Zhang ◽

Xiangtian Xu ◽

Yanjun Shen ◽

Hailiang Jia ◽

...

Keyword(s):

Compressive Strength ◽

Shear Strength ◽

Concrete Structures ◽

Freezing Temperature ◽

Frost Damage ◽

Freezing And Thawing ◽

Shear Properties ◽

Freeze Thaw ◽

Steel Bar ◽

Concrete Interface

Frost damage of concrete has significant effects on the safety and durability of concrete structures in cold regions, and the concrete structures after repair and reinforcement are still threatened by cyclic freezing and thawing. In this study, the new-to-old concrete interface was reinforced by steel bar. The shear strength of the new-to-old concrete interface was tested after the new-to-old combination was subjected to cyclic freeze–thaw. The effects of the diameter of the steel bar, the compressive strength of new concrete, the number of freeze–thaw cycles and the freezing temperatures on the shear properties of new-to-old concrete interface were studied. The results showed that, in a certain range, the shear strength of the interface was proportional to the diameter of the steel bar and the strength of the new concrete. Meanwhile, the shear strength of the reinforced interface decreased with the decreasing of the freezing temperature and the increasing of the number of freeze–thaw cycles.

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Durability of Structural Lightweight Concrete with Sintered Fly Ash Aggregate

Materials ◽

10.3390/ma13204565 ◽

2020 ◽

Vol 13 (20) ◽

pp. 4565 ◽

Cited By ~ 1

Author(s):

Lucyna Domagała

Keyword(s):

Fly Ash ◽

Moisture Content ◽

Water Absorption ◽

Water Permeability ◽

Lightweight Concrete ◽

Concrete Strength ◽

Initial Moisture Content ◽

Cement Matrix ◽

Secondary Importance ◽

Freeze Thaw

The aim of this study was to present the problem of durability of structural lightweight concrete made of a sintered fly ash aggregate. The issue of durability was researched for 12 concrete series in terms of their water absorption, water permeability, and freeze-thaw resistance. Additionally, the microstructure of several concretes was analyzed with a scanning electron microscope (SEM). In the durability research, the influences of the following parameters were taken into consideration: The initial moisture content of sintered fly ash (mc = 0, 17–18, and 24–25%); the aggregate grading (4/8 and 6/12 mm); and the water-cement ratio (w/c = 0.55 and 0.37). As a result of various compositions, the concretes revealed different properties. The density ranged from 1470 to 1920 kg/m3, and the corresponding strength ranged from 25.0 to 83.5 MPa. The durability research results of tested lightweight concretes showed that, despite considerably higher water absorption, a comparable water permeability and comparable or better freeze-thaw resistance in relation to normal-weight concrete may be present. Nevertheless, the fundamental requirement of lightweight concrete to achieve good durability requires the aggregate’s initial moisture content to be limited and a sufficiently tight cement matrix to be selected. The volume share of the cement matrix and aggregate, the cement content, and even the concrete strength are of secondary importance.

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Influence of Frost Damage on Chloride Penetration into Concrete

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.711.359 ◽

2016 ◽

Vol 711 ◽

pp. 359-366

Author(s):

Peng Zhang ◽

Folker H. Wittmann ◽

Yan Ru Wang ◽

Tie Jun Zhao ◽

Guan Ting

Keyword(s):

Service Life ◽

Frost Damage ◽

Chloride Penetration ◽

Capillary Absorption ◽

Freeze Thaw ◽

Durability Design ◽

Design Service Life ◽

Before And After ◽

Deteriorating Process ◽

Selection Of

In most national and international codes for durability design, service life is estimated after selection of one single and dominant deteriorating process such as carbonation, chloride penetration or frost attack. Application of existing codes has shown, however, that the predicted service life is not reached in practice in most cases. Early damage occurs and as a consequence expensive repair measures become frequently necessary, long before the design service life is reached. One reason for this discrepancy is certainly the fact that in practice each dominant deteriorating process is usually accompanied by other aggravating processes. In this contribution capillary absorption of different types of concrete is studied first. The influence of an increasing number of freeze-thaw cycles on capillary absorption of water is studied first, then chloride penetration before and after exposure to a certain number of freeze-thaw cycles was determined experimentally. It was found that an increasing number of freeze-thaw cycles increases chloride penetration significantly, and hence reduces service life in aggressive environment. It can be concluded that for realistic service life prediction the interaction between frost damage and chloride penetration has to be taken into consideration in regions with low temperatures.

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HEAT RESISTANCE, WATER RESISTANCE AND FROST DAMAGE RESISTANCE OF COLD SETTING EPOXY RESIN MORTARS

Transactions of the Architectural Institute of Japan ◽

10.3130/aijsaxx.269.0_1 ◽

1978 ◽

Vol 269 (0) ◽

pp. 1-10

Author(s):

SADAHIRO INOUE

Keyword(s):

Heat Resistance ◽

Epoxy Resin ◽

Water Resistance ◽

Frost Damage ◽

Damage Resistance ◽

Cold Setting

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Frost damage of bricks composing a railway tunnel monument in Central Japan: field monitoring and laboratory simulation

Natural Hazards and Earth System Science ◽

10.5194/nhess-5-465-2005 ◽

2005 ◽

Vol 5 (4) ◽

pp. 465-476 ◽

Cited By ~ 18

Author(s):

C. Thomachot ◽

N. Matsuoka ◽

N. Kuchitsu ◽

M. Morii

Keyword(s):

Frost Damage ◽

Field Monitoring ◽

Laboratory Simulation ◽

Freezing Front ◽

Railway Tunnel ◽

Central Japan ◽

Freeze Thaw ◽

Unidirectional Freezing ◽

Vacuum Saturation ◽

Laboratory Results

Abstract. Bricks of tunnels and bridges of Usui Pass railway (Japan) exposed to north are subject to frost damage. Average depth of erosion due to detachment of angular blocks is around 1-1.5 cm. In order to assess this weathering and to understand its mechanism, an experimental study was carried out in the field and laboratory. Field monitoring showed the combination of seasonal and diurnal freezing with a maximum of heave when the freezing front reached 5 cm depth. Bricks taken from the site were submitted to unidirectional freezing at capillary and vacuum saturation in the laboratory. Results showed that frost damage of bricks was favoured by high saturation level and repetition of freeze-thaw cycles.

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The use of grinded andesite-sand and foaming-agent to improve the porosity of foam-concrete

MATEC Web of Conferences ◽

10.1051/matecconf/201819501018 ◽

2018 ◽

Vol 195 ◽

pp. 01018

Author(s):

Rommel Erwin ◽

Rusdianto Yunan ◽

Dawara Kiki Ruris ◽

Eddy S Tri

Keyword(s):

Compressive Strength ◽

Lightweight Concrete ◽

Foam Concrete ◽

Foaming Agent ◽

Compressive Strength Test ◽

Concrete Type ◽

Compressive Strength Of Concrete ◽

Porosity Measurements ◽

Highly Porous ◽

High Absorption

There has been an increase in the demand for the use of green concrete in construction. Foam concrete is a lightweight concrete type that has the characteristics of being lightweight, low-strength, highly porous with a high absorption rate and with good insulation properties. The use of sand smoothed andesite in the manufacture of foam concrete is expected to improve the properties of porous concrete and make it more suitable for use. In this study, 120 mortar cubes with the size of 5 cm was used for the density testing, compressive strength testing and porosity testing of foam concrete. Foam concrete is made by mixing cement, sand andesite of 1:2.75 and w/c 0.7 and a foaming agent, which are respectively 1%,2%, 3%, and 4%. Porosity measurements with the soaking method and the concrete compressive strength test were performed, respectively at the age of 7, 14, 21, and 28 days. The results showed that the increase in use of a foaming agent will cause a reduction in the density and the compressive strength of the concrete. While the porosity of foam concrete which is measured at the "volume of permeable void" will increase with the decreasing density and compressive strength of concrete.

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