Evaluating Low-Temperature Stiffness and Brittle Point in Elastomers

1944 ◽  
Vol 17 (1) ◽  
pp. 107-115
Author(s):  
Floyd L. Graves ◽  
Arnold R. Davis
Keyword(s):  
Low Temperature ◽  
Test Methods ◽  
Brittle Point ◽  
The Times ◽  
Method Of Evaluation

Abstract The illustrations indicate some of the possibilities in our method of evaluation. The urgency of the times requires that all workers come forward with any new test methods that may be of value in developing better compounds, without consuming valuable time investigating all of the possibilities and limitations of such methods. Possibly other workers will wish to apply the methods described, in their studies on the effects of plasticizers, curing times and temperatures, reenforcing fillers, etc., in low-temperature compounding of the various new elastomers being pressed into service today.

An Improved Low-Temperature Brittleness Test

1949 ◽  
Vol 22 (3) ◽  
pp. 820-827 ◽  
Author(s):  
E. F. Smith ◽  
G. J. Dienes
Keyword(s):  
Low Temperature ◽  
Temperature Interval ◽  
Statistical Study ◽  
Distribution Curve ◽  
Simple Analysis ◽  
Reasonable Amount ◽  
Brittle Point

Abstract An improved low-temperature brittleness tester, capable of testing five specimens simultaneously, is described. All machine specifications conform to A.S.T.M. Method D 746-44T. Data are presented which show that many elastomers do not possess a sharp brittle point but are characterized by a distribution of failures over a temperature interval. The improved brittleness tester makes it possible to carry out the necessary statistical study of the distribution of per cent failures versus temperature with a reasonable amount of work. A simple analysis of the resulting distribution curve is presented.

scholarly journals Influence of Bitumen Type and Asphalt Mixture Composition on Low-Temperature Strength Properties According to Various Test Methods

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2118 ◽  
Author(s):  
Marek Pszczola ◽  
Cezary Szydlowski
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Cooling Rate ◽  
Strength Properties ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Mixture Composition ◽  
Tension Stress ◽  
Strength Reserve

In regions with low-temperatures, action transverse cracks can appear in asphalt pavements as a result of thermal stresses that exceed the fracture strength of materials used in asphalt layers. To better understand thermal cracking phenomenon, strength properties of different asphalt mixtures were investigated. Four test methods were used to assess the influence of bitumen type and mixture composition on tensile strength properties of asphalt mixtures: tensile strength was measured using the thermal stress restrained specimen test (TSRST) and the uniaxial tension stress test (UTST), flexural strength was measured using the bending beam test (BBT), and fracture toughness was measured using the semi-circular bending test (SCB). The strength reserve behavior of tested asphalt mixtures was assessed as well. The influence of cooling rate on the strength reserve was investigated and correlations between results from different test methods were also analyzed and discussed. It was observed that the type of bitumen was a factor of crucial importance to low-temperature properties of the tested asphalt concretes. This conclusion was valid for all test methods that were used. It was also observed that the level of cooling rate influenced the strength reserve and, in consequence, resistance to low-temperature cracking. It was concluded that reasonably good correlations were observed between strength results for the UTST, BBT, and SCB test methods.

scholarly journals Nanostructured Bitumen with Nanocarbon

2019 ◽  
Vol 21 (4) ◽  
pp. 317 ◽  
Author(s):  
B.B. Teltayev ◽  
A.A. Kalybai ◽  
G.G. Izmailova ◽  
S.R. Rossi ◽  
E.D. Amirbayev ◽  
...  
Keyword(s):  
Low Temperature ◽  
Test Methods ◽  
Structure Variation ◽  
Temperature Resistance ◽  
Chemical Indicators ◽  
Excess Surface ◽  
The Cost ◽  
Physical And Chemical ◽  
Low Temperature Resistance

Physical and chemical indicators of bitumen quality of grade BND 70/100 with the added carbon nanopowder 2% by weight have been studied by laboratory test methods and analysis. High reaction ability of nanopowder particles and concentration of excess surface and internal energy in them have been determined, which provide the increase of low-temperature resistance, aggregate strength, and improvement of rheological properties of nanostructured bitumen. Essential structure variation has been proved: the increase of asphaltenes and oils content for 9% and 7.2% respectively due to the decrease of resins for 16.2% by weight. Methods have been discussed for preparing a liquid nanocarbon mix, adding of the mix into bitumen and homogenization of the bitumen. Some economic indicators have been represented which influence essentially the reduction for the cost value of the nanostructure bitumen.

scholarly journals Experimental study on the compression characteristics of soft soil based on low temperature effect

2021 ◽  
Vol 9 (4B) ◽  
Author(s):  
Jian Zhang ◽  
◽  
Chunpeng Han ◽  
Jiayi Tian ◽  
Qingjie Dong ◽  
...  
Keyword(s):  
Low Temperature ◽  
Phase Change ◽  
Compression Test ◽  
Variable Temperature ◽  
Soft Soil ◽  
Test Methods ◽  
Variable Load ◽  
Compression Tests ◽  
Different Temperatures ◽  
Freezing Condition

Based on the characteristics of long annual freezing time and short suitable construction period of soft soil in cold region, this paper discusses the feasibility of foundation treatment of soft soil in freezing-thawing layer under freezing condition. The deformation characteristics of soft soil in freezing-thawing layer in Hulunbuir area in China are studied by using two compression test methods, namely, constant temperature and variable load (CTVL) test, variable temperature and variable load (VTVL) test. The compressibility indexes under different temperatures and consolidation pressures are obtained. The research shows that the freezing-thawing soft soil has large compressibility, the maximum strain of CTVL test is 19.89%, and the maximum compression of VTVL test can reach 18.16%. The results of CTVL compression tests show that when the soil temperature is in the range of severe phase change (-1.5℃-0℃), the temperature change has the greatest influence on the compression coefficient of soil. The result of VTVL compression test shows that some additional deformation occurs under the action of low temperature. The additional deformation is further increased when the soil is under high consolidation pressure and in the severe phase change (-1.5℃-0℃).

A Study of Stiffness Testing of Elastomers at Low Temperatures

1955 ◽  
Vol 28 (1) ◽  
pp. 335-347
Author(s):  
F. S. Conant
Keyword(s):  
Low Temperature ◽  
Temperature Region ◽  
Low Temperatures ◽  
Temperature Limit ◽  
Test Methods ◽  
Beam Method ◽  
Stiff Material ◽  
Rubberlike Materials ◽  
Good Agreement

Abstract In light of the above discussion, it does not appear logical to choose a “best” test for determining low-temperature moduli. A study of the data as a whole indicates that the correlation between the two sets of values from the simple beam-method (laboratories C-1 and C-2) are closest, but there is nothing to show that they are the most valid. It should be emphasized that, in the temperature region of greatest technical importance, that is, where the rubber is changing from its ordinary flexible state to a hard stiff material, the different tests show good agreement. A low-temperature limit of serviceability would be close to −80° F for the Hevea gum and −60° F for the GR-S by each of the methods studied. Another conclusion that might well be reached by a study of the test methods and data presented is that the term “modulus”, as applied to rubberlike materials, is rather vague unless the method of obtaining that modulus is also given.

scholarly journals Stability Evaluation and Mechanism of Asphalts Modified With Various Rubber Powder Contents

2021 ◽  
Vol 7 ◽  
Author(s):  
Hengxiao Xue ◽  
Yuanbo Cao ◽  
Qi Liu ◽  
Hongfei Zhang ◽  
Mingliang Zhang
Keyword(s):  
Low Temperature ◽  
Softening Point ◽  
Stability Index ◽  
Test Methods ◽  
Segregation Index ◽  
Rubber Powder ◽  
Evaluation Indexes ◽  
Modified Asphalt ◽  
Powder Content ◽  
Storage Properties

Ground tires are one of the main sources of urban solid waste. Rubber powder-modified asphalt provides an effective method to solve the problem, and it presents good high- and low-temperature performance in sustainable pavement construction. However, the storage properties of rubber powder-modified asphalts prepared from the traditional low-temperature shear mixing method are unstable, which restricts their application. In this study, four test methods (the softening-point test; the dynamic shear rheological test; the Laboratory Asphalt Stability Test; and fluorescence image analysis) and six evaluation indexes (the softening-point difference Sdiff, the segregation percentage Sp, the segregation index Ise, the segregation rate Rs, the degradation rate Rd, and the stability index Ist) were employed to analyze the storage abilities of asphalts modified by various activated rubber powder contents. The results show that the storage properties have a positive correlation with rubber powder content in the modified asphalt, and a rubber powder content of 60% is proven to be the optimum mixing amount. The rubber powders can distribute uniformly in the asphalt matrix when mixed below the optimum mixing amount; otherwise a rubber powder agglomeration is formed. The quantitative morphology analysis results are in good agreement with the laboratory test conclusions. The activated rubber powder shows better compatibility compared with ordinary rubber powders and presents a promising method to treat waste ground tires.

Sign in / Sign up

Export Citation Format

Share Document