CN102936420A - Modified asphalt joint grouting glue for severe-cold roads - Google Patents

Abstract

The invention first selects low temperature resistant asphalt, and then increases the proportion of SBS in an SBS modified asphalt joint grouting glue to improve the high temperature performance, the low temperature performance and the ageing resistance of the asphalt. Especially with improved low temperature embrittleness and greatly enhanced severe cold resistance, the invention is a modified asphalt joint grouting glue for severe-cold roads. The modified asphalt joint grouting glue is specifically characterized by comprising: 100 parts of 120# petroleum asphalt, 15-20 parts of SBS, 8-10 parts of tackifying resin, 0.2-1 part of an anti-aging agent, 8-10 parts of synthetic rubber, 2-8 parts of a softener, and 0.2-0.4 part of an anti-stripping agent.

Description

Severe cold type road modified asphalt base joint grouting glue

Affiliated technical field

The present invention is a kind of pavement maintenance material, is particularly useful for the gap-grouting material of the bituminous pavement etc. in severe cold type area, is the modern technique in the pavement maintenance material.

Technical background

Road gap-grouting glue in actual use, the failure rate of north cold area base joint grouting glue is apparently higher than other areas, this phenomenon causes that we are to the attention of base joint grouting glue low-temperature performance research, base joint grouting glue is many-sided (such as day and night temperature, quantity of precipitation, the volume of traffic on the low temperature road with failure cause under the condition, Pavement Structure Design, the form of mending front crack and degree etc.), but the performance of base joint grouting glue especially low-temperature performance itself is main internal cause, so the research and development of severe cold type joint sealant are just imperative.In order to solve the problems of the technologies described above, just need us to work out more reliably joint sealant of performance.

Summary of the invention

The present invention at first selects low temperature resistant pitch, then in SBS modifying asphalt joint sealant, increase the share of SBS, improve the high-temperature behavior of pitch, low-temperature performance and ageing resistance, especially improved its low-temperature embrittleness, significantly having improved anti-severe cold, is a kind of severe cold type modified asphalt for road joint sealant.

Because the major ingredient of road seal gum is pitch, so the gordian technique of low temperature modification road seal gum mainly is the selection problem of soft pitch.The project implementation key is mainly to be conceived to pitch visco-elasticity behavior under cold condition, environment for use by the simulation compound, such as aging, clay environment, the temperature effect pattern of pitch is discussed, focus on the test of the phase transformation of substances, utilize second-order transition temperature to carry out the evaluation of asphalt performance as index, screen available pitch as base-material, with SBS properties-correcting agent compatibility, the share of SBS in joint sealant also will be increased to more than a times of common joint sealant again.

Its specific features is: 100 parts of No. 120 asphalt stone oily bitumens, SBS15～20 part, tackifying resin: 8-10 part, anti-aging agent: 0.2-1 part, synthetic rubber: 8-10 part, tenderizer: 2-8 part, antistripping agent: 0.2-0.4 part

Description of drawings

Fig. 1: the relation of storage modulus/loss tangent and temperature variation

Fig. 2: the variation of pitch tired factor in 0～35 ℃

Fig. 3: the relation of storage modulus and loss tangent and temperature variation

Fig. 4: the variation of pitch tired factor in 0～35 ℃

Fig. 5: pitch loss tangent peak variation with temperature

(a) No. 70 pitch and different Ratio of filler bitumen clay

(b) No. 90 pitch and different Ratio of filler bitumen clay

Fig. 6: pitch storage modulus and temperature variation

(a) No. 70 pitch and different Ratio of filler bitumen clay

(b) No. 90 pitch and different Ratio of filler bitumen clay

Fig. 7: pitch out-of-phase modulus and temperature variation

(a) No. 70 pitch and different Ratio of filler bitumen clay

(b) No. 90 pitch and different Ratio of filler bitumen clay

$\ln \mathrm{\η}=\ln A+\frac{\mathrm{\Δ}{E}_{\mathrm{\η}}\mathrm{\δ}}{\mathrm{RT}}---\left(1\right)$

In the formula: Δ E _η---be flow-activation energy, kJ/mol;

η---be apparent viscosity, Pas;

A, R---be constant.

Fig. 8: viscosity and temperature and activation energy variation relation

(a) logarithm viscosity and temperature derivative

(b) activation energy and Ratio of filler bitumen

Fig. 9: Ratio of filler bitumen is on the impact of asphalt cement low-temperature creep characteristic

-12 ℃ of creep rates

Figure 10: second-order transition temperature and PG classification cryogenic temperature

(a)-12 ℃ stiffness modulus

(b) second-order transition temperature and creep stiffness corresponding temperature

Embodiment:

1 test method

No. 50, No. 70, No. 90 matrix pitches in sea were as subjects during test was adopted, adopt TFOT, two kinds of methods of RTFOT wear out, near the limestone matter breeze of enjoying a double blessing the employing Jinan carries out the configuration of clay, mainly rheological characteristics under the differing temps of pitch and clay thereof is studied, the main instrument that adopts has: dynamic shear rheometer (U.S. Waters-Ta AR2000ex type), low-temperature bending rheometer (U.S. Cannon TE-BBR), rotary thin film in drying oven, thin film oven etc.Need to prove, aspect the glass transition test, always indirectly with the variation of certain relevant nature foundation as glass transition, such as performance perameters such as refraction coefficient, specific heat, roasting change, storage modulus, out-of-phase modulus, loss tangents, wherein, about the speed of the response of volume and thermodynamic property is greater than the mechanical response behavior, therefore, measured second-order transition temperature is relatively low.Simultaneously, in concrete measuring process, the glass transition of high molecular polymer easily is subject to the impact of alternating temperature speed and survey frequency condition, therefore, when the vitrifying of pitch and asphalt cement is tested, the employing dynamic shear rheometer is carried out, adopt the indexs such as Young's modulus, out-of-phase modulus, loss tangent to characterize, and for fear of the impact of different tests condition, all samples all adopt identical test parameter setting, that is: velocity of shear 10rad/s, proof stress 100Pa carry out the temperature scanning between 0～35 degree.

2 results and discussion

2.1 the phase of matrix pitch changes

According to the test conditions of prior setting, No. 50, No. 70, No. 90 matrix pitches are carried out respectively temperature scanning between the 0-35 degree, obtain the variation relation of dynamic mechanical index and temperature, as shown in Figure 1.

Found out by Fig. 1, the storage modulus of pitch is linear growth along with the reduction of temperature, until near the second-order transition temperature, obvious flex point occurs, pitch presents vitreous state character, and modulus occurs and reduce phenomenon, illustrate pitch at this moment structure destroy; Loss tangent also Internal Friction Peak shape occurs at the second-order transition temperature point, because the concussion campaign of pitch has been subject to relatively large friction resistance, in-fighting increases, and forms an extreme value peak, is called in theory the main of superpolymer and changes.Internal Friction Peak is over against the second-order transition temperature point of answering superpolymer.Wherein 5.Number, the second-order transition temperature of No. 70, No. 90 pitches reduces successively, be respectively near 7,5,1 degree.The difference of this second-order transition temperature causes to some extent Integral lifting of pitch other performances between the 0^35 degree, and similar variation phenomenon also appears in the tired factor, and the tired factor flex point of different labels pitch corresponding temperature order is identical with the second-order transition temperature order, sees Fig. 2

Found out by Fig. 2, under the same temperature, No. 50 the tired factor is maximum, and No. 90 minimums are reacted and determined fatigue performance of asphalt mixture under the same periphery factor and the relation of pitch label.

2.2 the impact of aged asphalt vitreous state

Aging impact on pitch (seal gum), from the loss tangent aspect, can find out obviously that the different aging pitch low-temperature phase is changed to some extent affect, see Fig. 3, Fig. 4. thin film oven aging and rotary thin film in drying oven are roughly the same on the low temperature phase transformation impact of No. 70 matrix pitches, can make the second-order transition temperature of pitch carry 1～2 degree, the flexible reduction reduced the fatigue performance of bituminous material.

2.3 breeze is on clay and low-temperature performance impact

Breeze is sieved the part of getting below the 0.075mm, and according to Ratio of filler bitumen Fa=0.6,1.0,1.6 carry out the preparation of asphalt cement, carry out.Temperature scanning test in the-35C interval, the data variation that obtains is shown in Fig. 5～7.On the temperature corresponding points that occur from modulus change and Internal Friction Peak, No. 70 pitch and clay thereof be according to Ratio of filler bitumen 0,0.6,1.0,1.6 order, and Tg is respectively 5,12, and 15,20; 90 pitches and clay thereof be according to Ratio of filler bitumen 0,0.6,1.0,1.6 order, and Tg is respectively 1,11, and the adding of 13,18 explanation breezes has improved the low temperature glass transition temperature of asphalt roads seal gum, has increased the fragility of system.This point also has identical embodiment in low-temperature bending beam test (BBR), namely increases breeze and has improved minimum design temperature index in the classification of seal gum PG performance.

The attenuating of temperature to the motor capacity reduction of asphalt system, thereby raises the viscosity of pitch and seal gum system thereof.General, when the polymer temperature is higher than second-order transition temperature, the close Andrade equation 1 that seemingly meets of viscosity and temperature, be the logarithm of complex viscosity and the inverse relation of being in line of temperature, Fig. 8 medium pitch sealed colloid ties up to and all presents such relation in the certain temperature section, illustrates that the seal gum system before the second-order transition temperature conforms to this equation.Before second-order transition temperature, we can calculate according to slope of a curve the activation energy of sealing seal gum system, the activation energy variation relation of seal gum system can illustrate these problems among Fig. 7, it is the increase of breeze, improved the activation energy of whole system, viscosity is increased, and the temperature sensitivity of seal gum system is increased; Simultaneously, other has the scan-data of the tired factor also to illustrate, the interpolation of breeze has increased the tired factor of seal gum greatly, has reduced the fatigue performance of seal gum.When being lower than second-order transition temperature, bituminous seal glue presents typical vitreous state elasticity speciality, its motion activation energy no longer is perpetual index, but the function of temperature, and determining character of use and behavior under pitch (seal gum) cold condition, these indexs can select pitch simply supported beam BBR low-temperature bending test, DMA instrument to estimate because nsR instrument self limits and can not directly measure.

2.4 the seal gum low-temperature performance is index related

Utilize the BBR test apparatus that the asphalt cement creep behaviour under the different Ratio of filler bitumen of pitch is tested.Result's demonstration, breeze has increased the low temperature stiffness modulus of asphalt cement, has reduced its creep speed, bitumen stiffness modulus (S) when Fig. 9 is the p-12C of different Ratio of filler bitumen, the influence curve of creep speed (m).

Thus, we can make a correlation analysis to the second-order transition temperature under different pitches and the different Ratio of filler bitumen and the minimum design temperature in the asphalt performance classification, get that m equals 0.3 in the classification of PG performance, corresponding temperature point when S equals 300MPa, and the second-order transition temperature point carries out, and sees Figure 10.As seen from the figure, between the minimum design temperature of second-order transition temperature and pitch good dependency is arranged, utilizing second-order transition temperature is significant as evaluation index.

3 conclusions

A) label of pitch and second-order transition temperature are inversely proportional to, and label is higher, and second-order transition temperature is lower; The adding of breeze can improve the second-order transition temperature of bituminous seal glue, the tired factor in the raising between warm area.And the minimum design temperature in pitch second-order transition temperature and the asphalt performance classification has good dependency, can be as the Low Temperature Performance Evaluation Indexes of estimating joint sealant.

B) about the consideration of test conditions.Because when DSR measures second-order transition temperature, the specified conditions of selecting, the result who measures under different condition is different, test frequency is higher, the modulus flex point that occurs and the position corresponding temperature of Internal Friction Peak are also higher, therefore testing the Tg index that obtains only can be as a kind of lateral comparison, and it is for referencial use that measuring method must rely on the performance index of the fast response times such as thermodynamics more accurately.For this condition restriction, can carry out across comparison by simulated roadway material different stressed, frequency state, obtain with actual use procedure in more approaching performance index, with reflection and explain actual fatigue, brittle failure (brittle rupture and ductile rupture) the behavior phenomenon that occurs.This can estimate the method for low temperature bituminous seal glue pavement performance preferably.

C) increase the share at joint sealant of SBS, also greatly improved the lower temperature resistance of joint sealant.

Claims (1)

1. severe cold type road modified asphalt joint sealant is characterized in that, No. 120 pitch oil, 100 parts of pitches, SBS15～20 part, tackifying resin 8-10 part, anti-aging agent 0.2-1 part, synthetic rubber 8-10 part, tenderizer 2-8 part, antistripping agent 0.2-0.4 part.

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