A structure and method for fixing a copper water stop between new and old concrete

Abstract

A structure and method for fixing a copper waterstop between new and old concrete mainly include a method, and the method comprises the following steps: Step (1), arranging shallow grooves on the surface of the old concrete; Step (2), arranging expansion bolt holes in the shallow grooves; Step (3), applying epoxy base liquid in the shallow grooves; Step (4), applying a lower layer of epoxy mortar bonding layer on the surface of the epoxy base liquid; Step (5), installing a copper waterstop sheet on the surface of the lower layer of epoxy mortar bonding layer, and fixing the copper waterstop with expansion bolts and pressing strips; Step (6), applying an upper layer of epoxy mortar layer on the surface of the copper waterstop; Step (7), applying epoxy base liquid on the surface of the upper layer of epoxy mortar, and then closing it with a dry-hardened mortar protective layer for natural curing. Step (8), pouring new concrete on the surface of the dry-hardened mortar protective layer. The structure and method for fixing a copper waterstop between new and old concrete provided by the present invention can significantly improve the construction efficiency and reduce the damage to the old concrete structure.

Description

Technical Field

[0001] The present invention relates to the field of concrete water stop, in particular to a structure and method for fixing a copper water stop between new and old concretes. Background Art

[0002] In the concrete structures of water conservancy and hydropower projects, such as diversion tunnels, retaining dams, sluice gates, water conveyance tunnels, etc., in order to achieve design requirements such as structural anti-seepage and leakage prevention, adaptation to load deformation, shock absorption and buffering, etc., the currently common technical measures are to set concrete grooves at construction joints, deformation joints and other parts, embed copper water stop sheets in the grooves, and then fill and fix the copper water stop sheets with new concrete or asphalt. On the one hand, this method requires chiseling deep grooves on the old concrete base surface, with high labor intensity and long working hours; on the other hand, the bonding strength between the new concrete or asphalt filling layer and the copper water stop is not high, and there is a risk of interlayer peeling failure under the action of a higher water head. In addition, during the construction of the crown arch, filling new concrete or asphalt into the concrete groove with an opening downward is more cumbersome.

[0003] For old concrete structures, due to the existence of steel bars, the chiseling difficulty is great, and during the process of forming the base surface by chiseling deep grooves, the old concrete structure is severely damaged; filling new concrete or asphalt in the concrete deep groove, the quality cannot be guaranteed, which is determined by the shrinkage characteristics of the materials themselves.

[0004] Therefore, how to simplify the copper sheet water stop structure and its construction technology on the premise of ensuring the water stop effect has become a key problem to be solved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a structure and method for fixing a copper water stop between new and old concretes, which can simplify the copper sheet water stop structure and its construction technology on the premise of ensuring the water stop effect.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A structure for fixing a copper water stop between new and old concretes includes a shallow groove, in which a copper water stop sheet is arranged. The copper water stop sheet is placed on a lower epoxy mortar bonding layer and locked by expansion bolts; the lower part of the copper water stop sheet and the expansion bolts are sealed by an upper epoxy mortar bonding layer, and a new concrete layer is poured on the surface of the upper epoxy mortar bonding layer.

[0008] The copper water stop sheet has an L-shaped structure, with a total width of 30 cm to 60 cm and a thickness of 1.2 mm to 2.5 mm. One side of the copper water stop is longitudinally arranged in the shallow groove, and the other side extends outward from the middle of the old concrete section, and the length extending out of the shallow groove is 12 cm to 25 cm.

[0009] A method for fixing a copper water stop between new and old concretes includes the following steps:

[0010] Step (1): Set shallow grooves (1) on the old concrete surface;

[0011] Step (2): Drill holes in an array at the bottom of the shallow grooves (1) and install expansion bolts (4);

[0012] Step (3): Uniformly apply epoxy-based liquid to the bottom of the shallow grooves (1) and let it air-dry naturally for a period of time;

[0013] Step (4): Uniformly scrape and apply epoxy mortar on the bottom of the shallow grooves (1) and compact and level it to form a lower-layer epoxy mortar bonding layer (3);

[0014] Step (5): Install copper waterstops (2) on the lower-layer epoxy mortar bonding layer (3), use flattened steel bars (7) on the surface and install expansion bolts (4), and tighten the nuts (8);

[0015] Step (6): After installing the copper waterstops (2), apply an upper-layer epoxy mortar layer (5) on the surface of the copper waterstops to form an upper-layer epoxy mortar bonding layer (5), and the upper-layer epoxy mortar bonding layer (5) seals the lower part of the copper waterstops (2) and the expansion bolts (4);

[0016] Step (7): Apply epoxy-based liquid on the surface of the upper-layer epoxy mortar bonding layer (5), then use dry-hardened mortar (9) for protection and seal it, and cure it naturally for 3 to 5 days;

[0017] Step (8): Pour a new concrete layer (6) on the surface of the dry-hardened mortar (9) protection layer.

[0018] In step (1), the cross-section of the shallow grooves is trapezoidal, the depth of the shallow grooves is 2 cm to 10 cm, and the bottom width is 15 cm to 50 cm.

[0019] In step (1), for construction projects where the old concrete surface has not yet been formed, a base surface with pre-cast belt shallow grooves can be used.

[0020] In step (3), the layer thickness of the epoxy-based liquid is 0.5 mm to 1.0 mm, and the natural air-drying time is 40 min to 90 min.

[0021] In step (4), the thickness of the lower-layer epoxy mortar bonding layer is 5 mm to 3 cm.

[0022] In step (5), the installation of the copper waterstops needs to be completed within 4 hours after filling the lower-layer epoxy mortar bonding layer. Before installing the copper waterstops, the intersection part of the copper waterstops and the newly poured concrete surface is processed with plane concavity and convexity to prevent dislocation and void formation when the copper waterstops contact the newly poured concrete.

[0023] In step (6), the thickness of the upper-layer epoxy mortar bonding layer is 1.0 cm to 3 cm.

[0024] In step (7), the thickness of the dry - hard mortar protective layer is 5.0 cm to 8.0 cm.

[0025] The epoxy mastic is CW series epoxy mastic.

[0026] A structure and method for fixing a copper waterstop between new and old concretes of the present invention have the following technical effects:

[0027] 1). By using epoxy mastic as the bonding material, due to its large bonding strength (dry bonding with concrete at 28 days > 4.0 MPa or cohesive failure of concrete) and high compressive strength (compressive strength at 28 days > 95 MPa), the comprehensive mechanical properties of the waterstop structure can be improved, and the waterstop effect can be ensured.

[0028] 2). The conventional installation process of copper waterstops requires chiseling a deep concrete groove (generally not less than 40 cm wide × 40 cm deep), which is difficult to chisel, has low construction efficiency, damages the old concrete, and the vibratory compactness of the later - poured concrete or mortar is poor, especially in the crown - arch part. While in this application, by opening a shallow groove (the trapezoidal shallow groove is 15 cm - 40 cm wide and 2.0 cm - 10 cm deep), and implementing an epoxy mastic bonding layer and a pre - shrunk mortar protective layer in layers in the shallow groove, the construction difficulty can be reduced, the construction efficiency can be improved, the damage to the old concrete can be reduced, and the construction process flow can be further simplified.

[0029] 3). For the crown - arch part, the combined use of pre - shrunk mortar and epoxy mastic can avoid the technical problem of poor vibratory compactness of the later - poured concrete or mortar, ensure that there is no sagging during the construction of the crown - arch, can be filled densely, and is convenient for operation.

[0030] 4). The installation and fixation of the copper waterstop sheet are carried out by using flattened steel bars and bolts, which can meet the construction of any working surface of the copper waterstop sheet, greatly reduce the construction difficulty of the top waterstop structure, and at the same time ensure that the technical problem of weakening the waterstop effect caused by the shear dislocation of the concrete and the waterstop sheet due to the stress and strain changes of the concrete structure does not occur. This not only facilitates the construction but also can achieve the purpose of enhancing the waterstop effect.

[0031] 5). By using epoxy mastic with high impermeability grade and frost - resistance grade to bond and fix the copper waterstop sheet, compared with the conventionally used concrete and asphalt materials, the integrity and service life of the waterstop structure can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below with reference to the drawings and embodiments:

[0033] Figure 1 It is a schematic structural diagram of the present invention.

[0034] In the figure: shallow groove 1, copper waterstop 2, lower epoxy mortar bonding layer 3, expansion bolt 4, upper epoxy mortar bonding layer 5, new concrete layer 6, flattened steel bar 7, nut 8, dry hard mortar 9. Detailed implementation method

[0035] As Figure 1 shown, a structure for fixing a copper waterstop between new and old concrete includes a trapezoidal cross-section shallow groove 1, in which an L-shaped copper waterstop 2 is provided. The copper waterstop 2 is placed on the lower epoxy mortar bonding layer 3 and locked by an expansion bolt 4, a flattened steel bar 7 and a nut 8, and the upper epoxy mortar bonding layer 5 is sealed by dry hard mortar 9. The lower horizontal part of the copper waterstop 2 and the expansion bolt 4 are sealed by the upper epoxy mortar bonding layer 5, the surface of the upper epoxy mortar bonding layer 5 is sealed by dry hard mortar 9, and a new concrete layer 6 is poured on the surface of the dry hard mortar 9.

[0036] A method for fixing a copper waterstop between new and old concrete includes the following steps:

[0037] (1) Base surface treatment: For the formed old concrete surface, shallow grooves 1 are set on the surface. The depth H1 of the trapezoidal shallow groove 1 is 2 cm to 10 cm, and the bottom width L1 is 15 cm to 50 cm. After grooving, use high-pressure water to clean the floating dust and debris on the groove surface to make the base surface basically flat. For the unformed old concrete surface, during the pouring process of the old concrete, a pre-poured belt shallow groove standard base surface can be adopted, with the same dimensions as above. The corresponding steel bar arrangement and formwork structure for pouring need to be adjusted accordingly, which can effectively ensure that the old concrete surface is not disturbed and damaged by the copper waterstop construction.

[0038] (2) Layout and drilling: Layout and drill holes in a rectangular distribution in two columns and multiple rows. The column spacing L2 = 5 cm to 10 cm, and the row spacing is 1 m. After drilling, clean the floating ash and install the expansion bolt 4. The specification of the expansion bolt 4 is: M12, and the length is 5 cm to 9 cm.

[0039] (3) Coating epoxy base liquid: Mix the two components of epoxy base liquid A and B (CW710 series epoxy mortar) in a mass ratio of 1:0.4 and mechanically stir for 2 min to 4 min. After stirring evenly, apply it evenly on the bottom of the trapezoidal groove, and the coating thickness is 0.5 mm to 1.0 mm.

[0040] (4) Filling the epoxy mortar bonding layer: 40 min to 90 min after the epoxy base liquid is applied, mix and stir the two components of epoxy mortar A and B in a mass ratio of 1:(0.2 to 0.5), and after 3 min to 5 min, evenly apply and scrape the epoxy mortar on the bottom of the trapezoidal groove and compact and level it. The layer thickness of the lower epoxy mortar bonding layer 3 is 5 mm to 3 cm.

[0041] (5) Installation of copper waterstop: After the lower epoxy mortar bonding layer 3 is leveled, within 4 hours, flatten the steel bar and tighten the bolts to complete the installation and fixation of the copper waterstop 2 on the old concrete surface. Before installing the copper waterstop 2, the intersection part of the copper waterstop 2 and the newly poured concrete surface should be processed with plane concavity and convexity to prevent dislocation and void formation when the copper waterstop 2 contacts the newly poured concrete.

[0042] (6) Application of outer epoxy mortar coating: After the copper waterstop 2 is installed, apply epoxy mortar to form the upper epoxy mortar bonding layer 5, with a layer thickness of 1.0 cm to 3 cm for the upper epoxy mortar bonding layer 5.

[0043] (7) Sealing and curing: Apply epoxy base liquid on the surface of the upper epoxy mortar bonding layer 5, and then use dry-mixed mortar 9 (mass ratio of cement: medium sand: water is 1:1~3:0.3~0.4) for protective layer sealing. The thickness of the dry-mixed mortar protective layer 9 is 5.0 cm to 8.0 cm, and natural curing is carried out for 3 to 5 days.

[0044] (8) Pouring of new concrete: Pour new concrete on the surface of the dry-mixed mortar.

[0045] The epoxy mortar is CW series epoxy mortar, and its main properties are: compressive strength at 28 days > 90 MPa, tensile strength at 28 days > 13 MPa, dry bonding strength with concrete at 28 days > 4.0 MPa (or concrete failure), which can improve the comprehensive mechanical properties and durability of the waterstop structure.

[0046] The copper waterstop is made of T2 type purple copper, with an L-shaped structure, a total width of 30 cm to 60 cm, and a thickness of 1.2 mm to 2.5 mm. One side of the copper waterstop is longitudinally arranged in the middle of the trapezoidal groove section engraved, and is installed and fixed by internal bonding with epoxy mortar and external bolt anchoring. The other side extends outwards from the middle of the old concrete section, with a length L3 of 12 cm to 25 cm.

[0047] The traditional waterstop method is to engrave a deep groove, bury the waterstop, and then backfill with concrete. There are still problems with the contact between new and old concrete. Compared with the L-shaped waterstop structure, only the penetration path is changed (lengthened), and it cannot achieve a good waterstop effect. The shallow engraving groove method we adopted, and then through the epoxy mortar material, layering this construction site, ensures a good transition and elastic deformation buffer between new and old concrete. The contact between new and old concrete is not a hard contact. This filling ensures the sealing of the water seepage channel and reduces the construction period requirements brought by the on-site engraving groove process.

[0048] Although some existing processes use epoxy glue, they still engrave deep grooves and do not have layered treatment for the epoxy glue. The layered progressive transition between new and old concrete creates space for the adaptability between new and old materials, that is, the transition layer, and the allowable elastic deformation space is larger.

[0049] Example 1:

[0050] Select the side wall part of the grouting adit of a hydropower station. A shallow grooving 1 with a depth of 4.0 cm, a length of 2.0 m, a surface width of 50 cm, and a bottom width of 40 cm is chiseled on the old concrete. After chiseling the old concrete, use high-pressure water to clean the surface dust and loose covering, ensure the base surface of the shallow grooving 1 is flat, and then dry it. Lay out the lines and drill holes in a rectangular distribution. The holes are arranged in two columns and multiple rows, with a column spacing of 10 cm and a row spacing of 1 m. After drilling, clean the floating ash and install M12 expansion bolts 4 with a length of 9 cm. Mix the two components of epoxy base liquid A and B in a mass ratio of 10:4 and mechanically stir for 3 min, and then evenly apply 0.5 mm thick epoxy base liquid on the old concrete. 50 min after the epoxy base liquid is applied, mix the two components of epoxy mortar A and B in a mass ratio of 10:3 and mechanically stir for 4.0 min, and then evenly apply and scrape the epoxy mortar to fill the base surface of the old concrete, compact and level it. The thickness of the epoxy mortar bonding layer is 1.5 cm. Immediately install and fix the copper water stop 2 after the epoxy mortar bonding layer is filled. Use a flat steel bar with a length of 2.0 m and a thickness of 4 mm and tighten the bolts on the expansion bolts 4. The installation process is completed within 3 h. Immediately fill the epoxy mortar covering layer after the copper water stop 2 is installed. The thickness of the epoxy mortar covering layer is 2.5 cm. Cure naturally for 3 d.

[0051] The new and old concrete prepared by the present invention has technical parameters: C25W12F200.

[0052] The epoxy mortar prepared by the present invention has technical parameters: 28-day compressive strength of 98.6 MPa, 28-day tensile strength of 14.8 MPa, 28-day dry bonding strength with concrete of 4.7 MPa, and 28-day wet bonding strength with concrete of 3.5 MPa.

[0053] Example 2:

[0054] Select the bottom part of the grouting adit of a hydropower station. Chisel a shallow groove 1 with a depth of 3.5 cm, a length of 2.0 m, a surface width of 50 cm, and a bottom width of 40 cm on the old concrete; after chiseling the old concrete, use high-pressure water to clean the surface floating dust and loose covering materials to ensure that the base surface of the shallow groove 1 is flat, and then dry it. Lay out the lines and drill holes in a rectangular distribution. The holes are arranged in two columns and multiple rows, with a column spacing of 10 cm and a row spacing of 1 m. After drilling, clean the floating ash and install 4 M12 expansion bolts with a length of 9 cm. Mix the two components of epoxy base liquid A and B in a mass ratio of 10:4 and mechanically stir for 3 min, and then evenly apply 0.5 mm epoxy base liquid on the old concrete. 50 min after the epoxy base liquid is applied, mix the two components of epoxy mortar A and B in a mass ratio of 10:3 and mechanically stir for 4.0 min, and then evenly apply and scrape the epoxy mortar to fill the base surface of the old concrete, compact and level it. The thickness of the epoxy mortar bonding layer is 1.0 cm. Immediately install and fix the copper water stop after the epoxy mortar bonding layer is filled. Use a flat steel bar with a length of 2.0 m and a thickness of 4 mm and tighten the bolts on the expansion bolts 4. The installation process is completed within 2.5 h. Immediately fill the epoxy mortar covering layer after the copper water stop 2 is installed. The thickness of the epoxy mortar covering layer is 2.5 cm. Cure naturally for 3 d, and then sprinkle water for curing for 4 d.

[0055] The new and old concrete prepared by the present invention has technical parameters: C25W12F200.

[0056] The epoxy mortar prepared by the present invention has technical parameters: 28-day compressive strength of 98.6 MPa, 28-day tensile strength of 14.8 MPa, 28-day dry bonding strength with concrete of 4.7 MPa, 28-day wet bonding strength with concrete of 3.5 MPa, and frost resistance grade F250.

[0057] Example 3:

[0058] Select the top arch part of the grouting adit of a certain hydropower station. Chisel a shallow groove 1 with a depth of 3.0 cm, a length of 1.0 m, a surface width of 50 cm, and a bottom width of 40 cm in the old concrete; after chiseling the old concrete, use high-pressure water to clean the surface dust and loose covering materials to ensure that the base surface of the shallow groove 1 is flat, and then dry it. Lay out and drill holes in a rectangular distribution. The holes are arranged in two columns and multiple rows, with a column spacing of 10 cm and a row spacing of 50 cm. After drilling, clean the floating ash and install 4 M12 expansion bolts with a length of 9 cm. Mix the two components of epoxy base liquid A and B in a mass ratio of 10:4 and mechanically stir for 3 min, and then evenly apply 0.7 mm epoxy base liquid on the old concrete. 45 min after the epoxy base liquid is applied, mix the two components of epoxy mortar A and B in a mass ratio of 10:3 and mechanically stir for 3.5 min, and then evenly scrape and fill the epoxy mortar on the base surface of the old concrete, compact and level it. The thickness of the epoxy mortar bonding layer is 1.0 cm. After the epoxy mortar bonding layer is filled, immediately install and fix the copper waterstop. Use a flat steel bar with a length of 2.0 m and a thickness of 4 mm and tighten the bolts on the expansion bolts 4. The installation process is completed within 2.5 h. After the copper waterstop is installed, immediately fill the epoxy mortar covering layer, and the thickness of the epoxy mortar covering layer is 2.0 cm. Cure naturally for 3 d, and then sprinkle water for curing for 25 d.

[0059] For the new and old concrete prepared by the present invention, its technical parameters are: C25W12F200.

[0060] For the epoxy mortar prepared by the present invention, its technical parameters are: 28-day compressive strength of 98.6 MPa, 28-day tensile strength of 14.8 MPa, 28-day dry bonding strength with concrete of 4.7 MPa, 28-day wet bonding strength with concrete of 3.5 MPa, and frost resistance grade F250.

Claims

1. A structure for fixing a copper waterstop between new and old concrete, characterized in that: It includes a shallow groove (1), in which a copper water stop sheet (2) is provided. The copper water stop sheet (2) is placed on the lower epoxy mortar bonding layer (3) and locked by expansion bolts (4); the lower part of the copper water stop sheet (2) and the expansion bolts (4) are sealed by the upper epoxy mortar bonding layer (5), and the surface of the upper epoxy mortar bonding layer (5) is sealed by dry - hard mortar (9) and a new concrete layer (6) is poured. The copper water stop sheet (2) is of an L - shaped structure, with a total width of 30 cm to 60 cm and a thickness of 1.2 mm to 2.5 mm. One side of the copper water stop sheet (2) is longitudinally arranged in the shallow groove (1), and the other side extends outward from the middle of the old concrete section. The length extending out of the shallow groove (1) is 12 cm to 25 cm; the depth of the shallow groove (1) is 2 cm to 10 cm.

2. A method for fixing a copper waterstop between new and old concrete, characterized in that: It includes the following steps: Step (1): Set a shallow groove (1) on the old concrete surface. Step (2): Drill holes in an array at the bottom of the shallow groove (1) and install expansion bolt holes. Step (3): Uniformly apply epoxy - based liquid to the bottom of the shallow groove (1) and let it air - dry naturally for a period of time. Step (4): Uniformly scrape and spread epoxy mortar on the bottom of the shallow groove (1) and compact and level it to form the lower epoxy mortar bonding layer (3). Step (5): Install the copper water stop sheet (2) on the lower epoxy mortar bonding layer (3). The copper water stop sheet (2) is of an L - shaped structure. Use flattened steel bars (7) on the surface and install expansion bolts (4), then tighten the nuts (8). Step (6): After installing the copper water stop sheet (2), apply the upper epoxy mortar bonding layer (5) on the surface of the copper water stop sheet (2) to form the upper epoxy mortar bonding layer (5), and the upper epoxy mortar bonding layer (5) seals the lower part of the copper water stop sheet (2) and the expansion bolts (4). Step (7): Apply epoxy - based liquid on the surface of the upper epoxy mortar bonding layer (5), then use dry - hard mortar (9) for protection and sealing, and cure naturally for 3 to 5 days. Step (8): Pour a new concrete layer (6) on the surface of the dry - hard mortar (9) protection layer.

3. The method for fixing a copper waterstop between new and old concrete according to claim 2, characterized in that: In step (1), the cross - section of the shallow groove (1) is trapezoidal, the depth of the shallow groove (1) is 2 cm to 10 cm, and the bottom width is 15 cm to 50 cm.

4. The method for fixing a copper waterstop between new and old concrete according to claim 2, characterized in that: In step (1), for construction projects where the old concrete surface has not been formed, a base surface with a pre - cast shallow groove (1) can be used.

5. The method for fixing a copper waterstop between new and old concrete according to claim 2, characterized in that: In step (3), the layer thickness of the epoxy - based liquid is 0.5 mm to 1.0 mm, and the natural air - drying time is 40 min to 90 min.

6. The method for fixing a copper waterstop between new and old concrete according to claim 2, characterized in that: In step (4), the thickness of the lower epoxy mortar bonding layer (3) is 5 mm to 3 cm.

7. The method for fixing a copper waterstop between new and old concrete according to claim 2, characterized in that: In step (5), the installation of the copper water stop sheet (2) needs to be completed within 4 hours after filling the lower epoxy mortar bonding layer (3). Before installing the copper water stop sheet (2), the part of the copper water stop sheet (2) intersecting with the newly poured concrete surface is processed with plane concavity and convexity, so that the contact between the copper water stop sheet (2) and the newly poured concrete is not likely to cause dislocation and void.

8. The method for fixing a copper waterstop between new and old concrete according to claim 2, characterized in that: In step (6), the thickness of the upper epoxy mortar bonding layer (5) is 1.0 cm to 3 cm.

9. The method for fixing a copper waterstop between new and old concrete according to claim 2, characterized in that: In step (7), the thickness of the dry - hard mortar (9) is 5 cm to 10 cm.

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