CN103741569B - A kind of old road based on drainage crack resistance enlarging splicing construction and method - Google Patents

Abstract

The invention discloses an old road extension splicing structure and method based on drainage and anti-cracking, belonging to the field of road engineering. The structure and method are characterized by layered milling of the old road structure from the splicing seam to the outside. Corresponding to the old road pavement structure, a certain width of the structural layer splicing steps is reserved for milling; the widening of the splicing pavement structure adopts density In the form of interphase combined structure, the thickness of the asphalt surface layer is the same as that of the old road asphalt surface layer, corresponding to the old road pavement structure and the internal lateral drainage of the subgrade, and a certain thickness of flexible asphalt treatment drainage base and semi-rigid material dense subbase are respectively set under the spliced asphalt surface , Graded crushed stone drainage cushion. Compared with the prior art, the splicing structure and method of the present invention solve the problems of poor internal drainage of the traditional pavement structure, uneven settlement of the new and old pavement, and cracking along the splicing seam. After splicing, the overall service life of the new and old pavement structure is long. It has good promotion and application value.

Description

A splicing structure and method for old road expansion based on drainage and anti-cracking

technical field

The invention relates to the field of road engineering, in particular to an old road extension splicing structure and method based on drainage and anti-cracking.

Background technique

With the rapid economic development and the rapid growth of highway traffic volume, the original highway traffic capacity cannot meet the needs of the society, so it is necessary to widen and rebuild. The splicing of the pavement is the biggest difficulty in the current reconstruction and expansion project, and it is also the key to quality control. The traditional pavement splicing method uses the same pavement structure as the old road, without considering the internal drainage of the old road structure and the deformation coordination of the new and old roads.

More than 90% of the active asphalt pavement in my country is semi-rigid base pavement structure. The advantage of this pavement structure is that the semi-rigid material has high rigidity and good plate performance. The disadvantage is that the semi-rigid material is prone to dry shrinkage and temperature shrinkage cracks. It also attenuates continuously with the traffic load. The semi-rigid base asphalt pavement has been operated for many years, and natural precipitation penetrates into the interlayer and interior of the structure through the road surface, cracks or the central divider, causing a large amount of water to accumulate in the structure. When using the traditional splicing method, because the newly paved semi-rigid material is very dense, it blocks the channel for the water to seep out of the old road structure, and the water that seeps into the structure is difficult to discharge, and the pavement structure appears quickly under the repeated action of driving load or freeze-thaw Diseases such as cracking, pumping, looseness and pits, especially at the joints are more prone to cracking and pumping diseases, which have a serious impact on driving safety. In addition, since the modulus of the semi-rigid base of the old road has been greatly attenuated, it is very different from the modulus of the semi-rigid base of the new road. If the same structure is adopted, it will inevitably cause deflection and settlement unevenness, cracks at the joints and a series of resulting problems. Derived diseases are inevitable.

Contents of the invention

The technical task of the present invention is to provide an old road extension splicing structure and splicing method based on drainage and anti-cracking for the above-mentioned deficiencies in the prior art. The new and old pavement structure widened by this method has smooth internal drainage, uniform and coordinated deformation, and will not cause structural defects such as cracking, pumping, pits, and settlements.

The technical task of the present invention is achieved in the following manner: an old road extension splicing structure based on drainage and anti-cracking, including the old road asphalt surface layer and the new road asphalt surface layer, and the old road base layer is laid under the old road asphalt surface layer, which is characterized by new Under the road asphalt surface, a certain thickness of flexible asphalt treatment drainage base, semi-rigid material dense subbase, graded crushed stone drainage cushion, joints between the new road asphalt surface and the old road asphalt surface, and new road asphalt surface The joints of flexible asphalt treatment drainage base, semi-rigid material dense subbase and old road base are all provided with structural layer splicing steps of a certain width.

The splicing method to achieve the above structure is characterized by layered milling of the old road structure layer from the splicing seam to the outside, corresponding to the old road pavement structure, and a certain width of the splicing steps of the structural layer is reserved for milling; widening the splicing pavement structure The dense-sparse combined structure is adopted, and the thickness of the asphalt pavement is the same as that of the old road asphalt pavement, corresponding to the old road pavement structure and the internal lateral drainage of the subgrade. Under the spliced asphalt pavement, a certain thickness of flexible asphalt treatment drainage base and semi-rigid materials are sequentially arranged. Dense subbase, graded crushed stone drainage cushion.

In order to prevent and delay reflective cracks and prevent the water on the road surface from penetrating downward along the joints, a layer of steel-plastic grille is laid longitudinally on the semi-rigid material dense sub-base at the junction of the new and old pavement. The width of the steel-plastic grille is 300~600cm; Filament unilateral singeing geotextiles with a width of 50~150cm are arranged on the bottom of the upper and middle surface of the asphalt surface.

In order to ensure that the joints between the old and new asphalt pavements are dense and impervious to water, during the construction of the joints of the asphalt pavement, the joint glue can be evenly applied to the side wall of the old asphalt pavement.

The splicing seam is preferably set on the center line of the outer marking line of the outer lane of the old road.

The old road structure layer is milled in layers from the splicing joint to the outside. The width of the splicing steps of each structural layer is: 15~20cm for each structural layer of the asphalt surface layer; 50~75cm for the base and subbase.

For the smooth drainage of new and old pavement structures and the relief of reflection cracks, the flexible asphalt treatment drainage base is preferably a special large-grain aggregate asphalt macadam mixture drainage layer with a thickness of 8-15cm; the semi-rigid material dense subbase is preferably cement or lime powder Coal ash stabilized crushed stone layer, thickness 45~60cm; graded crushed stone drainage cushion is arranged between the subbase and the top surface of subgrade, preferably open graded drainage type graded crushed stone cushion, thickness 15~20cm.

The design range of the porosity of the flexible asphalt treatment drainage base is 12% to 18%; the design range of the porosity of the graded crushed stone drainage cushion is 18% to 24%.

The gradation of the flexible asphalt treatment drainage base is measured by the percentage of each particle size mineral material passing through the standard size sieve hole, and its gradation range is:

31.5mm, 93%~100%; 19mm, 60%~75%; 9.5mm, 25%~38%; 1.18mm, 0~10%; 0.075mm, 0~3%.

The gradation of the graded crushed stone drainage cushion is measured by the percentage of each particle size mineral material passing through the standard size sieve hole, and its gradation range is:

31.5mm, 85%~100%; 26.5mm, 65%~85%; 16mm, 42%~67%; 9.5mm, 20%~40%; 4.75mm, 10%~27%; 1.18mm, 8%~ 20%; 0.6mm, 5%~18%; 0.075mm, 0%~5%.

The dense subbase of semi-rigid materials adopts the construction method of layered rolling and one-time curing to ensure the continuity and integrity of the layers.

Compared with the prior art, the splicing structure and method of the present invention have the following outstanding beneficial effects:

(1) This method is based on the mechanism of structural water damage, changing the seal water to be hydrophobic, and combining large-pore flexible special large-grain aggregate asphalt macadam mixture with water-permeable graded macadam to meet the requirements of the internal drainage system of the pavement structure , to solve the internal drainage problem of the widened lane and the adjacent old lane structure and the resulting damage to the pavement structure;

(2) This method follows the principle of pavement mechanics, and the designed combined pavement structure, the special large-grained aggregate asphalt macadam at the base and the graded macadam of the cushion have the load buffering function, and are spliced with the old road steps and set special anti-seepage and anti-corrosion The cracked materials form a complete overall structure of the new and old pavement, which solves the problems of uncoordinated deformation and uneven settlement, and greatly improves the overall performance of the widened new and old pavement structure;

(3) The base layer continuous paving method adopted in this method solves the problem of separation between the layers of the semi-rigid material dense base layer structure, which not only improves the overall bearing capacity of the old and new pavement structures, but also speeds up the construction speed.

Description of drawings

Accompanying drawing 1 is the full-sectional structure schematic diagram of the embodiment of splicing method of the present invention.

detailed description

Referring to the accompanying drawings in the description, a detailed description will be given below of an old road extension splicing structure and method based on drainage and anti-cracking of the present invention with specific embodiments.

Example:

1. Determine the specific structure of the old road

The specific structure of the old road is 4cmSMA-13 (upper asphalt surface layer 1) + 6cmAC-20C (middle asphalt surface layer 2) + 7cmAC-25C (lower asphalt surface layer 3) + 36cm cement stabilized gravel base 4 (constructed in two layers, The upper and lower bases are each 18cm) + 20cm lime stabilized soil subbase 5 + old roadbed 6.

2. Layered milling of the old road structure layer

The seams of the new and old roads are set on the center line of the outer marking line of the outer lane of the old road 7 . Carry out hierarchical milling to the old road structure layer from the splicing seam 7 to the outside, corresponding to the old road pavement structure, and reserve a certain width of the structural layer splicing steps 8 for milling.

The step widths corresponding to the middle asphalt surface course 2, the lower asphalt surface course 3, the cement stabilized macadam base course 4 and the subbase course 5 are 15cm, 15cm, 50cm, and 60cm, respectively.

3. Carry out splicing construction of new and old road structure layers

The specific splicing steps are:

a) After splicing subgrade 19 and compacting treatment, pave open graded drainage type graded crushed stone cushion 18

In order to solve the drainage problem on the top surface of the subgrade 6 of the old road, an open-graded drainage-type graded crushed stone cushion 18 with a thickness of 15 cm is designed and paved. The porosity of the graded crushed stone cushion ranges from 18% to 24%, and its gradation is measured by the percentage of mineral materials with various particle sizes passing through the standard size sieve hole. The design range is as follows:

31.5mm, 85%~100%; 26.5mm, 65%~85%; 16mm, 42%~67%; 9.5mm, 20%~40%; 4.75mm, 10%~27%; 1.18mm, 8%~ 20%; 0.6mm, 5%~18%; 0.075mm, 0%~5%.

b) Pave cement stabilized gravel subbase

In order to correspond to the pavement structure of the old road, low-dose cement-stabilized macadam 17 with a thickness of 15 cm and cement-stabilized macadam 16 with a thickness of 36 cm were paved as semi-rigid materials to compact the subbase. Based on the consideration of preventing and delaying reflective cracks and preventing water penetration, a layer of steel-plastic grid 11 with a width of 450 cm (low-dose cement stabilized gravel 17 and cement stabilized gravel between 16).

The cement-stabilized crushed stone subbase is constructed by layered rolling and one-time curing to ensure the continuity and integrity of the layers.

c) Set the lower seal layer 10

After the construction of the cement-stabilized crushed stone base course is completed, the surface is cleaned, and then the hot asphalt lower sealing layer 10 is sprinkled.

Sprinkle amount of hot asphalt in the lower seal layer is 1.2kg/m ² , and spread single-size asphalt ready-mixed gravel immediately after hot asphalt is spread, and the amount of spraying is 6kg/m ² .

The preferred specification of single particle size asphalt ready-mixed gravel is 5-10mm, the content of ready-mixed asphalt is 0.35%, and 70A asphalt or modified asphalt is used.

d) Paving special flexible large-grain aggregate asphalt macadam mixture drainage layer 15

In order to solve the internal drainage problem of the old pavement layer structure and prevent reflection cracks, a flexible special large-grain aggregate asphalt macadam mixture drainage layer 15 with a thickness of 10 cm is designed and paved.

The porosity of the special large particle aggregate asphalt macadam mixture is 12%-18%. 70A asphalt or modified asphalt is used, and the design asphalt content ranges from 2.9% to 3.5%. The gradation of large particle aggregate asphalt macadam is measured by the percentage of each particle size mineral material passing through the standard size sieve hole, and its gradation range is:

31.5mm, 93%~100%; 19mm, 60%~75%; 9.5mm, 25%~38%; 1.18mm, 0~10%; 0.075mm, 0~3%.

e) Laying the asphalt mixture surface course

After paving the drainage layer of special large-grain aggregate asphalt macadam mixture, pave densely graded asphalt mixture according to the original asphalt surface layer (upper asphalt surface layer 12, middle asphalt surface layer 13 and lower asphalt surface layer 14) to restore the asphalt Surface structure. Based on the consideration of preventing and delaying reflective cracks and preventing water penetration, two layers of filament unilateral singeing geotextile 9 with a width of 90 cm are arranged longitudinally at the bottom of the upper middle surface layer at the junction of the old and new pavement, and on the side wall of the old asphalt surface layer. Spread the caulk evenly.

Claims (8)

1. old road based on a drainage crack resistance enlarging joining method, it is characterised in that:

From splicing seam crossing, old road structure sheaf carrying out being layered milling laterally, corresponding with old road pavement structure, milling is reserved The structure sheaf splicing step of one fixed width；Widen splicing pavement structure and use combinative structure form between close lean phase, bituminous sheaths thickness Spending identical with old road thickness of bituminous surface, corresponding old road pavement structure and roadbed inner transverse draining, under splicing asphalt surface course Set gradually certain thickness flexible bituminisation Drainage Base, the closely knit underlayment of semi-rigid material, graded broken stone drainage blanket.

Old road based on drainage crack resistance the most according to claim 1 enlarging joining method, it is characterised in that: the old and new road surface is spelled Meet place, mould grid along longitudinally overlaying one layer of steel in the closely knit underlayment of semi-rigid material, steel mould the width of grid be 300～ 600cm。

Old road based on drainage crack resistance the most according to claim 1 and 2 enlarging joining method, it is characterised in that: new old road Stitching portion, face, being respectively provided with width bottom the upper middle surface layer of asphalt surface course is the 50～150cm wide monolateral geotechniques that singe of long filament Cloth.

Old road based on drainage crack resistance the most according to claim 3 enlarging joining method, it is characterised in that: asphalt surface course connects Old asphalt surface course sidewall uniform application base joint grouting glue during construction at seam.

Old road based on drainage crack resistance the most according to claim 4 enlarging joining method, it is characterised in that: described splicing connects Seam is arranged on the outside graticule centrage in track outside old road.

Old road based on drainage crack resistance the most according to claim 4 enlarging joining method, it is characterised in that: from splicing seam Place carries out being layered milling laterally to old road structure sheaf, and the width of each structure sheaf splicing step is respectively as follows: each structure of asphalt surface course Layer 15～20cm；Basic unit and underlayment 50～75cm.

Old road based on drainage crack resistance the most according to claim 1 enlarging joining method, it is characterised in that: described flexible drip Blue or green punishment Drainage Base, its thickness 8～15cm, voidage scope of design 12%～18%, pass through gauge with each particle diameter mineral aggregate Very little sieve aperture percentage, its grading limit is:

31.5mm, 93%～100%；19mm, 60%～75%；9.5mm, 25%～38%；1.18mm, 0～10%； 0.075mm, 0～3%；

The closely knit underlayment of described semi-rigid material uses cement or lime-flyash stabilization metalling, thickness 45～60cm；

Described graded broken stone drainage blanket is arranged between underlayment and roadbed end face, graded broken stone drainage blanket thickness be 15～ 20cm, voidage scope of design 18%～24%, with each particle diameter mineral aggregate by standard size sieve aperture percentage, its grading limit For:

31.5mm, 85%～100%；26.5mm, 65%～85%；16mm, 42%～67%；9.5mm, 20%～40%； 4.75mm, 10%～27%；1.18mm, 8%～20%；0.6mm, 5%～18%；0.075mm, 0%～5%.

Old road based on drainage crack resistance the most according to claim 7 enlarging joining method, it is characterised in that: described semi-rigid The closely knit underlayment of material uses the form of construction work of health preserving molding of layered rolling, it is ensured that interlayer is continuous whole.