Stone mastic asphalt and application thereof with steel slag as coarse aggregate
Technical field
The present invention relates to a kind of stone mastic asphalt, especially a kind of stone mastic asphalt with steel slag as coarse aggregate belongs to the technical field that asphalt is applied to highway pavement and slag recycling.The invention still further relates to the application of described stone mastic asphalt.
Background technology
Highway in China road surface layer generally adopts asphalt (AC).In recent years, in the high-grade highway upper layer, bring into use stone mastic asphalt (SMA).Stone mastic asphalt is to be extruded into skeleton by the embedding of gap grading coarse aggregate, the bitumastic filling skeleton gap that forms by pitch, fiber stabilizer, breeze and a small amount of fine aggregate and a kind of compound of forming, belong to a kind of closely knit-skeleton structure.Because stone mastic asphalt has remarkable characteristics such as anti-rut, cling property, bleeding and weather resistance, thereby becomes the ideal structure form of high grade highway pavement upper layer in recent years.The characteristics of stone mastic asphalt are: content of coarse aggregate height, asphaltic binder and breeze content height.Content of coarse aggregate accounts for more than 70%, and the mutual embedding of coarse aggregate to squeeze be the prerequisite that compound has good high-temperature stability, sliding resistance, thereby the quality of coarse aggregate is most important to the performance impact of stone mastic asphalt.This class compound require coarse aggregate tough and tensile, coarse, wear-resisting, corner angle are arranged and have good adhesivity with pitch.Using more coarse aggregate at present mainly is basalt and diabase, and these two classes building stones can satisfy the technical requirements of stone mastic asphalt to coarse aggregate.
But, along with the continuous expansion of highway in China construction scale, the demand of building stones being increased day by day, existing reserves can not satisfy the demands, and many geographic building stones can not satisfy the needs of road construction, thereby have greatly restricted the development of highway.Remote outward transport building stones make that again material cost increases, thereby highway construction cost is improved.And, the large scale mining building stones again havoc ecotope, the indirect loss that causes can't be retrieved.
Goal of the invention
The objective of the invention is to adopt the industrial waste of steelworks---slag replaces basalt and as the coarse aggregate of asphalt, a kind of stone mastic asphalt with steel slag as coarse aggregate is provided, to be used for the highway pavement upper layer, improve the road and use the life-span, reduce construction costs, and can recycle slag, reduce the pollution of steel cinder dust to environment.
Slag is the industrial waste of steelworks, always bulk deposition and nobody shows any interest in.Test shows that slag has outstanding wear resistance, is best one of the gathering materials of cling property.
Slag has the following advantages as the coarse aggregate of stone mastic asphalt:
1. from technical feature, slag is tough and tensile, coarse, corner angle are arranged, and has good adhesivity with pitch.And, contain Ca in the slag
2+, Mg
2+, Fe
3+, Al
3+, Mn
2+Etc. a large amount of positively charged ions, the material generation chemical reactions such as asphaltous acid in they and the pitch generate the pitch hydrochlorate, constitute chemisorbed layer on the slag surface, can increase the cohesive force of pitch and slag, and make asphalt have good water stability.Thereby slag is as the coarse aggregate excellent property of compound.
2. from economic angle, the slag low price, large-scale application can reduce cost of raw and processed materials, thereby reduces highway construction cost.And slag storage abundance, can alleviate the insufficient present situation of raw material supply greatly.
3. analyze from the environment aspect, the slag bulk deposition takies the big area place, and simultaneously, steel cinder dust pollutes has become one of principal element that influences environment.Utilize slag to address these problems rationally and effectively, and can produce the huge social benefit.
Summary of the invention
Stone mastic asphalt of the present invention (SMA), by gather materials, breeze, fiber stabilizer and asphaltic binder form, gathering materials comprises coarse aggregate and fine aggregate, described coarse aggregate adopts slag, fine aggregate adopts machine-processed sand as far as possible.Slightly, fine aggregate and breeze are called mineral aggregate.Described slag should be that the waste residue that steelworks is discharged was deposited more than 1 year, the material of the stable in properties that obtains after process magnetic separation again, the screening.The content of free calcium oxide should be controlled at below 2% in the slag.The technical feature of slag should satisfy the mechanical index requirement of stone mastic asphalt to coarse aggregate, sees Table 1.
Table 1 stone mastic asphalt is to the mechanical index requirement of coarse aggregate
Index | Technical requirements |
Building stones crush values (%) | Be not more than 25 |
Los Angeles wear(ing)value (%) | Be not more than 30 |
Water-intake rate (%) | Be not more than 2.0 |
Volume density (g/cm
3)
| Be not less than 2.60 |
Faller gill shape content (%) | Be not more than 15 |
Soft grain in aggregate (%) | Be not more than 1 |
Soundness (%) | Be not more than 12 |
To the bituminous adhesivity | Be not less than 4 grades |
Slightly, the cooperation ratio of fine aggregate should be decided according to grating situation separately.Generally speaking, among the SMA-16, the above coarse aggregate of 4.75mm adopts slag, and its consumption should be controlled at 68~80% of mineral aggregate weight, is controlled at about 75% as far as possible, and fine aggregate and breeze account for 20~32%.Bitumen aggregate ratio (being the mass ratio of asphaltic binder and mineral aggregate) is 5.0%~5.3%, and the lignin fibre consumption is 0.267% of a compound consumption.
Embodiment
Below specific embodiments of the invention are described in more detail.
Coarse aggregate in the SMA-16 stone mastic asphalt adopts the Shoudu Iron and Steel Co slag, and fine aggregate and breeze adopt limestone.The main character index of Shoudu Iron and Steel Co slag sees Table 2, and by comparison, table 3 is listed the basaltic main character index in Zhangjiakou.
Table 2 slag main character index table
Sieve aperture (mm) | Bulk density (g/cm
3)
| Water-intake rate (%) | Soft rock content (%) | Faller gill shape content (%) | Crush values (%) | Los Angeles abrasion (%) | Soundness (%) | Adhesivity |
????16 | ????3.21 | ????1.18 | Do not have | ???10.8 | ??14.4 | ????16 | ????4.7 | 4 grades |
????13.2 | ????3.201 | ????1.26 |
????9.5 | ????3.234 | ????1.24 |
????4.75 | ????3.127 | ????1.90 |
As seen from the table, the every performance of slag all can satisfy the technical requirements of stone mastic asphalt to coarse aggregate, and free calcium oxide content is 0.54% in the slag, and less than 2%, its stability meets the demands.
Table 3 basalt main character index table
Sieve aperture (mm) | Bulk density (g/cm
3)
| Water-intake rate (%) | Soft rock content (%) | Faller gill shape content (%) | Crush values (%) | Los Angeles abrasion (%) | Soundness (%) | Adhesivity |
??16 | ????2.808 | ??1.37 | Do not have | ???6.7 | ????12.8 | ????13.8 | ????1.0 | 4 grades |
??13.2 | ????2.812 | ??1.37 |
??9.5 | ????2.820 | ??1.45 |
??4.75 | ????2.817 | ??1.57 |
From above-mentioned table 2,3 slags and basaltic technical indicator, slag density is bigger than basalt.The ultimate compression strength that crush values, abrasion reflection are gathered materials, the trial value of slag is more bigger than basalt, illustrates that slag compressive strength rate basalt is lower slightly.
The mineral aggregate formate gradation composition of stone mastic asphalt of the present invention sees Table 4.
Table 4 mineral aggregate formate gradation composition table
Sieve aperture (mm) | Slag percent of pass (%) | Basalt percent of pass (%) | Grading limit (%) |
????16 | ????95 | ????95 | ????90~100 |
????13.2 | ????75 | ????75 | ????65~85 |
????9.5 | ????55 | ????55 | ????45~65 |
????4.75 | ????25 | ????26 | ????20~32 |
????2.36 | ????19.5 | ????19.5 | ????15~24 |
????1.18 | ????18 | ????18 | ????14~22 |
????0.6 | ????15 | ????15 | ????12~18 |
????0.3 | ????12.5 | ????12.5 | ????10~15 |
????0.15 | ????11.5 | ????11.5 | ????9~14 |
????0.075 | ????10 | ????10 | ????8~12 |
Make the performance difference of SMA coarse aggregate in order to compare slag and basalt, carry out the performance comparison test at two kinds of SMA that gather materials, the content of test is respectively high-temperature stability and the water stability of SMA.The test of high-temperature stability check is Marshall Test and wheel tracking test, and evaluation index is Marshall stability and dynamic stability.The test of water stability check is immersion Martens test and freeze thawing split test, and evaluation index is residual Marshall stability and freeze thawing cleavage strength ratio.In two groups of tests, except that coarse aggregate adopted slag and basalt respectively, all the other test conditionss were identical.Asphaltic binder adopts Panjin 90
#Heavy traffic asphaltum, modifying asphalt adopts the SBS modification, and volume 5%, fiber adopt German JR lignin fibre, fiber consumption 0.267%.Test-results sees Table 5, table 6, table 7.
The SMA-16 compound wheel tracking test result of table 5 Different Coarse Aggregates
The coarse aggregate kind | The binder kind | Bitumen aggregate ratio (%) | Dynamic stability (inferior/mm) | Code requirement (inferior/mm) |
Basalt | Modifying asphalt | ????5.9 | ????5538 | ??>3000 |
Non-modifying asphalt | ????5.6 | ????2453 | ??>1500 |
Slag | Modifying asphalt | ????5.3 | ????5559 | ??>3000 |
Non-modifying asphalt | ????5.0 | ????2400 | ??>1500 |
The SMA-16 compound Marshall Test result of table 6 Different Coarse Aggregates
The coarse aggregate kind | The binder kind | Bitumen aggregate ratio (%) | Stability (KN) | Code requirement (KN) | Flow valuve (mm) | Code requirement (mm) |
Basalt | Modifying asphalt | ????5.9 | ??8.59 | ??>6.0 | ?2.70 | ??2~5 |
Non-modifying asphalt | ????5.6 | ??8.25 | ??>5.5 | ?3.32 | ??2~4 |
Slag | Modifying asphalt | ????5.3 | ??12.41 | ??>6.0 | ?3.94 | ??2~5 |
Non-modifying asphalt | ????5.0 | ??8.20 | ??>5.5 | ?3.89 | ??2~4 |
Table 7 stone mastic asphalt water stability and active check
Compound | The slag asphalt | The basalt asphalt | Code requirement |
Cubical expansivity | ????0.6% | ????0.5% | Be not more than 1% |
Immersion Marshall stability ratio | ????90.0% | ????88.6% | Be not less than 80% |
The freeze thawing cleavage strength is than (TSR) | ????91.5% | ????86.7% | Be not less than 75% |
According to table 5 and table 6, from the dynamic stability of slag and basalt stone mastic asphalt and the test-results of Marshall stability, two kinds of dynamic stabilities that gather materials are more or less the same, Marshall stability also remains on same level, and, illustrate that two kinds are gathered materials and are used for stone mastic asphalt the high-temperature stability impact effect of compound is more or less the same all greater than code requirement.From the water stability angle, the residual Marshall stability of slag stone mastic asphalt and freeze thawing cleavage strength illustrate that than all greater than the basalt stone mastic asphalt water stability of slag stone mastic asphalt is better than the basalt stone mastic asphalt.
Performances such as the physics of slag of the present invention, chemistry and mechanics all meet does the high-grade highway road with the technical indicator of gathering materials, and is a kind ofly to can be used for the good of high-grade highway and gather materials.Every performance index of described slag stone mastic asphalt all can reach code requirement, and have good volume stability and higher mechanical property, can be used in the upper layer of high-grade highway, urban road bituminous pavement, this type of material excellent road performance, environmental sound and low price, thereby be with a wide range of applications.