A kind of density inspect method of compacting asphalt
Technical field
The present invention relates to the parametric measurement method of pitch and asphalt, particularly the density inspect method of compacting asphalt.
Background technology
The density measurement test of compacting asphalt is very general and important test in High Grade Bitumen Pavement detection, the asphalt test, and whether it accurately directly has influence on other important indicator of compacting asphalt such as the accuracy that calculate in voidage, mineral aggregate gap etc.At present, generally adopt " method of sealing with wax " to measure water-intake rate both at home and abroad greater than 2% the bituminous concrete or the bulk volume relative density of bituminous concrete moxture test specimen; China Ministry of Communications is numbered in " the highway engineering pitch and the asphalt testing regulations " of issue in 2000 in the T0707-2000 item experiment rules " compacting asphalt mixture density test (method of sealing with wax) ", and " method of sealing with wax " measured the method for compacting asphalt mixture density and step, required instrument tool and material, computing method etc. all specified in more detail; U.S.'s test has also been made specified in more detail to the requirement of " method of sealing with wax " test with materialogy meeting ASTM D 1188-89 item rules and 275 rules of the AASHTO T of u s. state highway worker association; The particular content of rules and requirement are similar substantially both at home and abroad.
The method that " method of sealing with wax " measures the compacting asphalt mixture density is: (1) takes by weighing the aerial quality m of dry test specimen
a(2) dry test specimen is sealed as sealing medium with paraffin, concrete steps are: at first dry test specimen is placed 4 ℃ of-5 ℃ of refrigerators to cool off at least 30 minutes, simultaneously with melted paraffin wax to its more than fusing point 5.5 ℃ ± 0.5 ℃, from refrigerator, take out dry test specimen then and immerse taking-up rapidly again after all surfaces is sealed by paraffin in the paraffin liquid immediately, place at normal temperatures after 30 minutes and obtain the test specimen of sealing with wax; (3) take by weighing the aerial quality m of the test specimen of sealing with wax
p(4) test specimen of will sealing with wax is put into the basket that immerses spill box, after soaking about 1 minute, takes by weighing quality m in the water of the test specimen of sealing with wax
cObtain the density of compacting asphalt at last according to the computing method of test specimen bulk density.In addition,,, need be coated with the skim talcum powder on dry test specimen surface in advance, take by weighing the test specimen quality m behind the powder coating for ease of removing deparaffnize if when test specimen also needs to do other tests after measuring density
s, and then the mensuration of sealing with wax.The shortcoming and defect that adopts " method of sealing with wax " to measure the compacting asphalt mixture density mainly contains: (1) test procedure is more loaded down with trivial details, to the requirement of test operation personnel and instrument and equipment than higher, particularly require very high to temperature controlling instruments, as required the accurate refrigerator of temperature control (4 ℃-5 ℃ of code requirements), electric furnace that temperature control performance is good or gas furnace are with the temperature of fusion of accurate control paraffin, because when carrying out " method of sealing with wax " test, whether test temperature control accurately has very big influence for accuracy of experimental results, temperature control out of true, paraffin enters the ratio of compacting bitumen mixture specimen internal pore also can be inconsistent, this will have influence on the comparability of each test findings, need spend a large amount of financial resources and dispose these special temperature controlling instrumentss, the equipment ordinary laboratory then is difficult to carry out " method of sealing with wax " test; (2) in the test process, may occur the crack after the cooling or move to collide with because of carelessness in the process of the test specimen of sealing with wax causing paraffin to split away off at the paraffin of each the surperficial intersection of test specimen of sealing with wax (as the curved surface of right cylinder test specimen and the intersection on two planes up and down) from the test specimen surface, thereby cause paraffin sealed test piece fully, these all can influence accuracy of experimental results; (3) seal process of test specimen need be with special anchor clamps, but no matter adopt which kind of anchor clamps, test specimen is being taken out from paraffin liquid and all can influence the outward appearance of paraffin sealed test piece with the process that test specimen is thrown off, even the paraffin on test specimen surface can be glued (in powder coating, such situation occurring), the sealing property of test specimen thereby influence is sealed with wax through regular meeting; (4) for the bigger test specimen in space, after even test specimen is freezing, the vasoliniment of high temperature can not be set in the test specimen surface immediately yet, the part vasoliniment still can enter the internal void of test specimen, the phenomenon that also exists some macropores to seal simultaneously, these also can influence accuracy of experimental results; (5) if when test specimen also needs to do other tests after measuring density,, also need to be coated with the skim talcum powder on dry test specimen surface in advance, and then take by weighing the gross mass m of talcum powder and dry test specimen for ease of removing deparaffnize
sBut this is difficult to operation in real process, because between the test specimen of dry talcum powder and drying without any cohesive force, talcum powder is easy to just be dropped or adhere on other contactants in the process of mobile test specimen, this can cause the whole test result to produce bigger error, must measure talcum powder in addition earlier and just can calculate the relative density of water and smeared the density of test specimen behind the talcum powder, this makes entire test become more complicated and has increased the factor that test error produces.
Summary of the invention
The objective of the invention is to overcome the shortcoming that prior art exists, the compacting asphalt mixture density that a kind of testing procedure is simple, testing apparatus is easy, the test result accuracy is high assay method is provided.
Purpose of the present invention is achieved through the following technical solutions: the density inspect method of this compacting asphalt comprises the steps---
(1) takes by weighing the aerial quality m of the dry test specimen of compacting asphalt
a
(2) adopt liquid silastic as sealing medium, concrete sealing step is: the bi-component of the liquid silastic that at first stirs, then liquid silastic being spread upon equably dry test specimen surface seals the test specimen surface fully, placed at normal temperatures again 10~45 minutes, and treated promptly to obtain the silicone rubber seal test specimen after liquid silastic solidifies; Described liquid silastic is the commercial goods, has the known relative density γ to water
s
(3) take by weighing the aerial quality m of silicone rubber seal test specimen
s
(4) the silicone rubber seal test specimen is put into the basket that immerses spill box, after soaking about 1 minute, take by weighing quality m in the water of silicone rubber seal test specimen
c
Obtain the density γ of compacting asphalt at last according to the computing method of test specimen bulk density
f
In the formula: γ
f---test specimen bulk volume relative density;
γ
s---liquid silastic is to the relative density of water under the normal temperature condition;
m
a---the aerial quality of dry test specimen, unit: gram;
m
s---the aerial quality of silicone rubber seal test specimen, unit: gram;
m
c---quality in the water of silicone rubber seal test specimen, unit: gram.
The density inspect method of compacting asphalt of the present invention compared with prior art has following advantage and effect:
(1) method of testing is simple, and testing apparatus is easy, need not temperature controlling instruments; Because liquid silastic has the rapid condensation characteristic, promptly at room temperature can be cured as the rubber-like silastic product apace, so in the dry test specimen seal process of compacting asphalt, both need not to carry out freezing to dry test specimen, also need not to resemble and want first heating liquid silicon rubber " method of sealing with wax ", so just, can save complicated and unworkable temperature control process, more can save high precision and expensive temperature controlling instruments such as refrigerator and gas furnace etc., reduced the difficulty of experimental implementation, made in general laboratory and particularly also can carry out water-intake rate in on-site the simple and easy laboratory greater than 2% compacting asphalt mixture density determination test.
(2) good seal performance of silicone rubber seal test specimen, precision of test result height, applied widely; Liquid silastic has higher viscosity, can spread upon the dry test specimen of asphalt surface easily, and has good effect for the dry test specimen in the big space of sealing; After liquid silastic solidifies, can form very thin one deck silastic surface on the test specimen surface, test specimen inside does not have water and enters when guaranteeing in the water of weighing sealed test piece quality; Simultaneously, silicon rubber has excellent sealing performance, can well test specimen be wrapped up, and can not occur " method of sealing with wax " test in cracking phenomena.
(3) experimental procedure simplification, simple to operate; Because silicon rubber has good demolding performace, just can be easily under the situation that is not coated with any separant with silicon rubber under the bitumen mixture specimen surfacial spalling, and can not cause any damage to the asphalt surface, peel off test specimen behind the silicon rubber and can be directly used in other test, this has just saved in " method of sealing with wax " needs to smear talcous step, eliminates and smears the influence of talcum powder to experimental precision.
(4) testing cost is low; For common test specimen, the consumption of liquid silastic is about 0.05g/cm
2If the space is big or the darker test specimen of texture, the consumption of liquid silastic is about 0.15g/cm
2So the testing cost of a compacting bitumen mixture specimen only needs about 5 yuan, and need not to drop into high accuracy temperature control equipment.
(5) save cost; The mode that liquid silastic adopts two kinds of components of A, B to mix use according to a certain ratio, under the situation that A, B component are separately preserved, liquid silastic can long preservation (about about 2 years), only after A, B component are mixed, just have the effect of rapid solidification, therefore can make things convenient for depositing of material, avoid the waste of material.
Embodiment
Below in conjunction with embodiment the present invention is done further detailed description, but embodiments of the present invention are not limited thereto.
Embodiment 1
Measure the density of asphalt core:
(1) adopting model is the electronic scale (maximum capacity is 2000g, sensibility reciprocal 0.01g) of JD2000-2, takes by weighing the aerial quality m of dry test specimen
a=508.37g;
(2) with the abundant uniform mixing of bi-component of liquid silastic, the surface that the liquid silastic that will mix and stir with scraper spreads upon dry test specimen equably seals the test specimen surface fully, test specimen is placed at room temperature 30 minutes again, treats to obtain sealed test piece after it solidifies;
(3) take by weighing the aerial quality m of sealed test piece
s=527.49g;
(4) hang up basket, immerse in the spill box, regulate water level, balance leveling or return-to-zero; Again sealed test piece is put into basket immersion, treat that reading is stable after, read quality m in the water
c=288.19g;
If when test specimen also needed to do other tests after measuring density, the silicon rubber of peelling off the test specimen surface got final product.
The correlation technique parameter (being provided by the manufacturer) of aforesaid liquid silicon rubber: viscosity is 500,000 centistokes, to the relative density γ of water
s=1.130g/cm
3
The bulk density of calculation testing piece:
With m
a=508.38g, m
s=527.49g, m
c=288.19g, γ
s=1.130g/cm
3The substitution following formula obtains: the relative bulk density of this test specimen is γ
f=2.286g/cm
3
Embodiment 2
Measure the density of the big test specimen of asphalt of rectangular parallelepiped:
(1) adopting model is the electronic scale (maximum capacity is 5100g, sensibility reciprocal 0.1g) of JA51001, takes by weighing the aerial quality m of dry test specimen
a=2922.7g;
(2) with the abundant uniform mixing of bi-component of liquid silastic, the surface that the liquid silastic that will mix and stir with scraper spreads upon dry test specimen equably seals the test specimen surface fully, test specimen is placed at room temperature 30 minutes again, treats to obtain sealed test piece after it solidifies;
(3) take by weighing the aerial quality m of sealed test piece
s=2978.6g;
(4) hang up basket, immerse in the spill box, regulate water level, balance leveling or return-to-zero; Again sealed test piece is put into basket immersion, treat that reading is stable after, read quality m in the water
c=1663.4g;
If when test specimen also needed to do other tests after measuring density, the silicon rubber of peelling off the test specimen surface got final product.
The correlation technique parameter (being provided by the manufacturer) of aforesaid liquid silicon rubber: viscosity is 500,000 centistokes, to the relative density γ of water
s=1.130g/cm
3
The bulk density of calculation testing piece:
With m
a=2922.7g, m
s=2978.6g, m
c=1663.4g, γ
s=1.130g/cm3 substitution following formula obtains: the relative bulk density of this test specimen is γ
f=2.309g/cm3.