Posterior installation method of water stop belt at concrete construction joint

Abstract

The application discloses a post-positioned installation method of a concrete construction joint waterstop, and relates to the technical field of waterproof construction of concrete structure construction joints, wherein the method comprises the following steps: opening a continuously-arranged waterstop installation groove on the surface of the construction joint of a first layer of completed concrete structure, cleaning and drying the groove wall and groove bottom and brushing a base treatment agent, embedding the waterstop into the installation groove and reserving a grouting gap between the two side edges of the waterstop and the groove wall, injecting waterstop sealing slurry into the grouting gap through a grouting pipe at a pressure of 0.3 MPa-0.6 MPa, and bonding and fixing the waterstop. The application solves the problems of construction joint leakage caused by the easy deviation of the pre-embedded installation position of the waterstop and the non-dense combination of the waterstop and the concrete, and has the advantages of accurate positioning of the waterstop, dense bonding, and reliable and long-lasting waterstop effect.

Description

Technical Field

[0001] This invention relates to the field of waterproofing construction technology for concrete construction joints, and in particular to a method for post-installation of a waterstop at a concrete construction joint. Background Technology

[0002] As large concrete structures develop towards ultra-long and large-volume designs, concrete inevitably needs to be poured in layers or sections. The resulting construction joints become one of the weakest links in the structural waterproofing system. The bond strength between the old and new concrete at construction joints is lower than that of monolithically poured concrete, and interconnected capillary pores easily form at the interface. Groundwater seeps into the structure along the construction joints, leading to leakage, steel corrosion, and reduced durability. To block seepage channels, waterstop components have been gradually introduced in engineering practice. The materials of waterstops have evolved from copper and steel plates to rubber, plastics, and water-swellable materials, and their installation method has gradually become a key process determining the waterproofing effect of construction joints.

[0003] In current engineering practice, waterstops are generally installed using a pre-embedded method: before the first layer of concrete is poured, the waterstop is positioned along the construction joint, with the lower half embedded in the first layer of concrete and the upper half exposed until the second layer of concrete is poured. During the pre-embedding process, the position of the waterstop is usually maintained by methods such as binding, clamping, or formwork. After the first layer of concrete is poured, the lower half of the waterstop is encased and fixed by concrete. However, this technical approach completely determines the final position of the waterstop by the pouring process, subjecting it to continuous impact and disturbance during concrete pouring and vibration.

[0004] This approach presents several technical challenges: First, the flowing concrete and vibration during pouring continuously push the waterstop, causing it to shift, twist, or even curl. After pouring, the waterstop's deviation from the construction joint's centerline cannot be measured or corrected, and in severe cases, it may even curl up and fail. Second, the bond between the embedded waterstop and the pre-poured concrete relies on the natural encapsulation of the grout during vibration. This interface easily traps air bubbles and loose particles, creating localized voids and seepage channels. Third, the interface between the subsequent concrete and the embedded waterstop is also not dense when vibration is insufficient, leaving both sides of the waterstop at risk of seepage. Furthermore, once the embedded waterstop is damaged or shifts beyond its limits during pouring, it cannot be inspected or repaired after completion, making the defect irreversible. Additionally, the waterstop is exposed to the construction environment for extended periods, making it susceptible to damage from trampling, mechanical impacts, and sun exposure. The combined effect of these problems results in a significant gap between the actual waterproofing effect of the waterstop at the construction joint and the design requirements, making it difficult to completely eliminate leakage problems at construction joints in the long term. Summary of the Invention

[0005] The main objective of this invention is to propose a post-installation method for waterstops at concrete construction joints. This method aims to ensure accurate positioning and tight bonding of the waterstop with the poured concrete during the waterproofing process of concrete construction joints, thereby solving the problems of misalignment and interface leakage of pre-embedded waterstops and improving the long-term waterproofing reliability of construction joints.

[0006] To achieve the above objectives, the present invention proposes a post-installation method for waterstops at concrete construction joints. This method involves installing a waterstop at the construction joint between a first-layer concrete structure and a second-layer concrete structure. The waterstop is embedded in a waterstop installation groove formed on the surface of the construction joint of the first-layer concrete structure. A grouting gap is reserved between the two edges of the waterstop and the sidewall of the waterstop installation groove. A grouting pipe is embedded within the grouting gap. The post-installation method for waterstops at concrete construction joints includes: A waterstop installation groove is opened on the surface of the construction joint of the first layer of concrete structure that has been poured. The waterstop installation groove is continuously arranged along the extension direction of the construction joint. The cross-section of the waterstop installation groove is an inverted trapezoid or a rectangle. The depth of the waterstop installation groove is 30mm to 50mm. The width of the waterstop installation groove is 1.2 to 1.5 times the width of the waterstop. The walls and bottom of the waterstop installation groove are cleaned and dried to remove laitance, loose particles and water, and a base treatment agent is applied to the walls and bottom of the waterstop installation groove. The waterstop is embedded in the waterstop installation groove. The top surface of the waterstop is lower than the upper surface of the first layer of concrete structure by 10mm to 20mm. Grouting gaps are reserved between the two sides of the waterstop and the side wall of the waterstop installation groove. Water-stop sealing grout is injected into the grouting gap through the grouting pipe. Under pressure, the water-stop sealing grout fills the grouting gap and bonds and fixes the waterstop strip to the waterstop strip installation groove. The injection pressure is 0.3MPa~0.6MPa.

[0007] In one embodiment, the step of creating a waterstop installation groove on the surface of the construction joint of the first layer of concrete structure that has already been poured includes: Lay out the boundary lines of the waterstop installation groove along both sides of the construction joint. The distance between the boundary lines and the center line of the construction joint is half the width of the waterstop plus 20mm to 30mm. The waterstop installation groove is excavated by first cutting the boundary and then chiseling away the groove body. First, a boundary cut with a depth of 30mm to 50mm is cut downward along the boundary line. Then, the concrete is chiseled away in sections between the boundary cuts on both sides to a depth of 30mm to 50mm. During the chiseling, the depth of each chiseling is controlled and damage to the steel bars in the first layer of concrete structure is avoided. The groove walls and bottom after chiseling are repaired to make the cross-sectional shape of the waterstop installation groove regular and the flatness deviation of the groove bottom not exceed 3mm / 2m.

[0008] In one embodiment, the waterstop is a rubber waterstop or a plastic waterstop, and the cross-sectional shape of the waterstop is embedded, externally attached, or composite. The step of embedding the waterstop strip into the waterstop strip mounting groove includes: The waterstop is cut according to the actual length of the waterstop installation groove. The cut length of the waterstop is 200mm to 300mm longer than the length of the waterstop installation groove so that an overlap is formed at both ends of the waterstop installation groove. An adhesive is evenly applied to the bottom and both sides of the waterstop. The adhesive is a neoprene rubber adhesive or a polyurethane adhesive. Place the waterstop coated with the adhesive into the waterstop installation groove, so that the center line of the waterstop coincides with the center line of the construction joint, with a deviation not exceeding 5mm.

[0009] In one embodiment, the step of pressurizing and injecting water-stopping and sealing grout into the grouting gap through the grouting pipe includes: A grouting pipe is arranged every 300mm to 500mm on both sides of the waterstop installation groove. The grouting pipe is a metal pipe or a rigid plastic pipe. The inner diameter of the grouting pipe is 8mm to 12mm. One end of the grouting pipe is inserted into the grouting gap, and the other end extends out of the upper surface of the first layer of concrete structure. The water-stop sealing grout is prepared as a water-swellable polyurethane grout or an epoxy resin grout, and the initial setting time of the water-stop sealing grout is 30 min to 90 min. Starting from one end of the construction joint, the water-stop sealing grout is injected into the grouting gap sequentially through each of the grouting pipes at an injection pressure of 0.3MPa to 0.6MPa. When grout overflows from an adjacent grouting pipe, the injection of the current grouting pipe is stopped and the grouting pipe is sealed.

[0010] In one embodiment, after the step of injecting the water-stop sealing grout into the grouting gap sequentially through each of the grouting pipes starting from one end of the construction joint, the method for post-installing the waterstop at the concrete construction joint further includes: After the initial setting of the water-stop sealing grout, supplementary grouting is performed on the grouting gap. The pressure of the supplementary grouting is 0.1MPa~0.2MPa, and the amount of grout used for supplementary grouting is 10%~20% of the amount of grout used in the initial grouting. After the water-stopping sealant has fully cured, the end of the grouting pipe extending out of the upper surface of the first layer of concrete structure is cut off, and the cut end of the grouting pipe is sealed with sealant.

[0011] In one embodiment, after the waterstop is fixed in the waterstop installation groove by the waterstop sealing grout, the post-installation method of the waterstop at the concrete construction joint further includes: A protective layer is placed over the waterstop, which is a cement mortar protective layer or a fine stone concrete protective layer, and the thickness of the protective layer is 20mm to 30mm. A layer of wire mesh or alkali-resistant fiberglass mesh is laid inside the protective layer, and the overlap width of the wire mesh or alkali-resistant fiberglass mesh is 100mm to 150mm. The surface of the protective layer is flush with or slightly lower than the upper surface of the first layer of concrete structure.

[0012] In one embodiment, the waterstop installation groove is opened when the first layer of concrete structure reaches more than 70% of the design strength and before the laitance layer on the surface of the construction joint has hardened but not completely dried. If the surface of the construction joint is completely dry, the surface of the construction joint should be moistened with water before opening the installation groove for the waterstop, so that the moisture content of the surface of the construction joint reaches 8% to 12%.

[0013] In one embodiment, the waterstop is a water-swellable rubber waterstop, and the expansion rate of the water-swellable rubber waterstop is 200% to 400%. Before embedding the waterstop into the waterstop installation groove, a layer of water-swellable putty strip is laid at the bottom of the waterstop installation groove. The width of the water-swellable putty strip is equal to the bottom width of the waterstop installation groove, and the thickness of the water-swellable putty strip is 5mm to 10mm.

[0014] In one embodiment, during the process of sequentially injecting the water-stop sealing grout into the grouting gap through each of the grouting pipes, a continuous weight is applied to the top surface of the waterstop, with a weight pressure of 0.01MPa to 0.03MPa, to prevent the waterstop from floating or shifting under the grouting pressure.

[0015] In one embodiment, the method for post-installing the waterstop at the concrete construction joint before pouring the second layer of concrete structure further includes: An interface treatment agent is applied to both sides of the waterstop installation groove. The interface treatment agent is a cement-based interface treatment agent or a polymer emulsion interface treatment agent. A cement mortar leveling layer is laid on the upper surface of the first layer of concrete structure. The thickness of the cement mortar leveling layer is 10mm to 20mm. The cement mortar leveling layer covers the surface area of ​​the construction joint where the waterstop installation groove is located, so as to ensure that the bonding surface between the second layer of concrete structure and the first layer of concrete structure is flat.

[0016] The technical solution of this invention solves the problem of leakage in construction joints caused by the easy displacement of the pre-embedded installation position of the waterstop and the poor bonding with the concrete. It has the advantages of accurate positioning of the waterstop, tight bonding, and reliable and long-lasting waterstop effect. The waterstop is installed by opening continuously arranged waterstop installation grooves on the surface of the construction joint of the first layer of concrete structure that has been poured. The groove walls and bottom are cleaned and dried and coated with a base treatment agent. The waterstop is embedded in the installation groove with a reserved grouting gap between its two sides and the groove wall. Waterstop sealing grout is injected into the grouting gap through the grouting pipe at a pressure of 0.3MPa~0.6MPa to bond and fix the waterstop. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic flowchart of an embodiment of the post-installation method for waterstop at concrete construction joints according to the present invention.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] To address this technical problem, this invention proposes a post-installation method for waterstops at concrete construction joints. This method involves installing a waterstop at the construction joint between a first-layer concrete structure and a second-layer concrete structure. The waterstop is embedded in a waterstop installation groove formed on the surface of the construction joint of the first-layer concrete structure. A grouting gap is reserved between the two edges of the waterstop and the sidewall of the waterstop installation groove, and a grouting pipe is embedded within the grouting gap.

[0024] Please see Figure 1 In one embodiment of the present invention, the method for post-installation of the waterstop at the concrete construction joint includes: S10, a waterstop installation groove is opened on the surface of the construction joint of the first layer of concrete structure that has been poured. The waterstop installation groove is continuously arranged along the extension direction of the construction joint. The cross-section of the waterstop installation groove is an inverted trapezoid or a rectangle. The depth of the waterstop installation groove is 30mm to 50mm. The width of the waterstop installation groove is 1.2 to 1.5 times the width of the waterstop. S20, the walls and bottom of the waterstop installation groove are cleaned and dried to remove laitance, loose particles and water, and a base treatment agent is applied to the walls and bottom of the waterstop installation groove. S30, the waterstop is embedded in the waterstop installation groove. The top surface of the waterstop is lower than the upper surface of the first layer of concrete structure by 10mm to 20mm. A grouting gap is reserved between the two sides of the waterstop and the side wall of the waterstop installation groove. S40, water-stop sealing grout is injected under pressure into the grouting gap through the grouting pipe. The water-stop sealing grout fills the grouting gap under pressure and bonds and fixes the waterstop strip in the waterstop strip installation groove. The pressure value of the pressure injection is 0.3MPa~0.6MPa.

[0025] For ease of understanding, the following explains some key terms in this embodiment: A construction joint is the interface between concrete poured in layers or sections when a concrete structure is poured in layers or sections.

[0026] A waterstop is a strip-shaped waterproof component installed at construction joints to prevent water from seeping in along the construction joints.

[0027] A waterstop installation groove is a groove opened on the surface of the construction joint of the first layer of concrete structure that has been poured, used to accommodate the waterstop.

[0028] Grouting gap refers to the gap reserved between the two edges of the waterstop and the side wall of the waterstop installation groove, which is used to inject waterstop sealing grout.

[0029] Water-stop sealing slurry refers to a slurry-like sealing material that is injected into grouting gaps and filled under pressure to bond and fix the waterstop strip.

[0030] Post-installation refers to the installation method of installing waterstops by slotting the surface of the construction joint after the first layer of concrete structure has been poured and reached a certain strength.

[0031] Primer is an interface material applied to the walls and bottom of the installation groove for waterstops to enhance the adhesion between the waterstop sealant and the concrete.

[0032] The protective layer refers to the cement mortar or fine aggregate concrete layer that covers the waterstop and is used to protect the waterstop from damage during subsequent construction.

[0033] This embodiment provides a method for post-installation of waterstops at concrete construction joints.

[0034] First, this method involves creating a groove for installing a waterstop on the surface of the construction joint of the first layer of concrete structure that has already been poured. Specifically, the boundary lines of the groove can be laid out along both sides of the construction joint, and then a boundary cut can be made along the boundary lines to form a boundary slit. Concrete can then be removed in sections between the boundary cuts on both sides. As an alternative approach, the groove can be created when the first layer of concrete structure has reached more than 70% of its design strength. If the surface of the construction joint is completely dry, it can be moistened with water until the moisture content is 8% to 12% before creating the groove.

[0035] Furthermore, the method includes cleaning and drying the walls and bottom of the groove for installing the waterstop, and then applying a primer to the walls and bottom. For example, laitance, loose particles, and accumulated water in the groove can be removed first, and the primer can be applied evenly after the walls and bottom of the groove are dry. Alternatively, the primer can be a material of the same system as the waterstop sealant to enhance the adhesion between the sealant and the concrete.

[0036] The method then involves embedding the waterstop into a waterstop installation groove, with the top surface of the waterstop 10mm to 20mm below the upper surface of the first layer of concrete structure, and leaving grouting gaps between the two sides and the sidewalls of the groove. Specifically, the waterstop can be cut to the actual length of the installation groove, and after applying adhesive to the bottom and two sides of the waterstop, it is placed into the groove, ensuring that the center line of the waterstop coincides with the center line of the construction joint, with a deviation not exceeding 5mm.

[0037] Based on this, the method includes pressurizing and injecting water-stop sealing grout into the grouting gap through grouting pipes at a pressure of 0.3MPa to 0.6MPa. The grout fills the grouting gap and bonds and fixes the waterstop. For example, grouting pipes can be arranged every 300mm to 500mm on both sides of the installation groove, and grouting can be carried out sequentially starting from one end of the construction joint. The grouting pipe is stopped when grout emerges from an adjacent grouting pipe, and the grouting pipe is then closed. As another implementation method, continuous weight can be applied to the top surface of the waterstop during the grouting process to prevent the waterstop from floating.

[0038] Meanwhile, after the waterstop is fixed, a protective layer can be covered on top of the waterstop, and an interface treatment agent can be applied and a cement mortar leveling layer can be laid before the second layer of concrete structure is poured.

[0039] In an embodiment of the present invention, the step of creating a waterstop installation groove on the surface of the construction joint of the first layer of concrete structure that has been poured includes: S11, lay out the boundary line of the waterstop installation groove along both sides of the construction joint. The distance between the boundary line and the center line of the construction joint is half the width of the waterstop plus 20mm to 30mm. S12, the waterstop installation groove is excavated in the order of first cutting the boundary and then chiseling the groove body. First, cut the boundary line downward to form a boundary cut with a depth of 30mm to 50mm. Then, chisel the concrete between the two boundary cuts in sections to a depth of 30mm to 50mm. When chiseling, control the depth of chiseling at one time and avoid damaging the steel bars in the first layer of concrete structure. S13, Repair the removed groove wall and bottom to make the cross-sectional shape of the waterstop installation groove regular and the flatness deviation of the groove bottom not exceed 3mm / 2m.

[0040] Specifically, the distance from the boundary line to the center line of the construction joint is half the width of the waterstop plus 20mm to 30mm, making the width of the installation groove 1.2 to 1.5 times the width of the waterstop. After the waterstop is embedded, a grouting gap of 10mm to 15mm width is naturally formed on both sides. It should be noted that the order of cutting the boundary first and then chiseling away the groove is the key to this step: pre-cutting along the boundary line to form a boundary slit, and confining the chiseling range between the boundary slits on both sides, can prevent the chiseling vibration force from being transmitted outward from the groove, causing the concrete at the edge of the groove to split and fall off, and ensuring the groove shape is regular; chiseling in sections and controlling the depth of each chiseling can avoid deep disturbance to the first layer of concrete structure and damage to the reinforcing steel. The flatness deviation of the groove bottom should not exceed 3mm / 2m, which provides a guarantee for the smooth placement of the waterstop and the uniformity of the grouting gap width.

[0041] Through the above technical solution, this application uses the sequence of "cutting the edge first, then chiseling away in sections, and then trimming" to open the groove, so that the shape, depth and flatness of the waterstop installation groove can be controlled, providing a regular and undamaged groove base for post-installation, and avoiding damage to the groove edge and structure caused by random chiseling.

[0042] In an embodiment of the present invention, the step of opening a waterstop installation groove on the surface of the construction joint of the first layer of concrete structure that has been poured further includes: S14, the timing of opening the waterstop installation groove is controlled to be before the first layer of concrete structure reaches more than 70% of the design strength and the laitance layer on the surface of the construction joint has hardened but not completely dried; if the surface of the construction joint is completely dry, the surface of the construction joint is first moistened with water before opening the waterstop installation groove, so that the moisture content of the surface of the construction joint reaches 8% to 12%.

[0043] Specifically, when the first layer of concrete reaches more than 70% of its design strength, the concrete has sufficient integrity, and grooving will not damage the structure. At this time, the laitance layer has hardened, the grooving boundary is clear, and the grooving wall is stably formed. It should be noted that grooving should be done before the laitance hardens but is completely dry. The residual moisture inside the concrete can be used to maintain a suitable moisture content in the grooving wall and bottom, which is beneficial for the penetration and bonding of the subsequent base treatment agent and waterproof sealant. If the surface of the construction joint is completely dry, it should be moistened with water to a moisture content of 8% to 12% to restore the moisture content of the grooving wall and bottom to a range conducive to bonding, and to avoid the dry concrete absorbing moisture from the sealant, which would cause the bonding interface to lose water and become loose.

[0044] Through the above technical solution, this application links the timing of grooving with the development of concrete strength and the interface moisture content, which not only ensures that the main structure is not damaged during grooving, but also creates favorable interface moisture conditions for subsequent grouting and bonding, thus ensuring the overall quality of the post-installation from the perspective of process sequence.

[0045] In an embodiment of the present invention, the steps of cleaning and drying the walls and bottom of the waterstop installation groove to remove laitance, loose particles and accumulated water, and applying a primer to the walls and bottom of the waterstop installation groove include: S21, Remove residual laitance, loose particles and accumulated water from the walls and bottom of the waterstop installation groove; S22. After the tank walls and bottom are dry, apply the primer evenly to the tank walls and bottom.

[0046] Specifically, if the laitance and loose particles generated during the grooving process remain in the trench, they will form an isolation layer between the waterproofing sealant and the concrete, weakening the bond strength. Accumulated water will dilute the sealant during grouting, altering its mix ratio and curing properties. It should be noted that the primer, applied to the cleaned and dried trench walls and bottom, penetrates the pores of the concrete surface and forms a bonding film, creating a continuous and strong bonded transition layer between the waterproofing sealant and the concrete, eliminating microscopic voids at the interface.

[0047] Through the above technical solution, this application pre-treats the bonding interface of the installation groove into a state free of laitance, water accumulation, and bonding film by a three-step interface treatment of "cleaning, drying, and applying a base treatment agent", thus laying the interface foundation for the dense filling and firm bonding of pressure grouting.

[0048] In an embodiment of the present invention, the step of embedding the waterstop strip into the waterstop strip mounting groove includes: S31, the waterstop is cut according to the actual length of the waterstop installation groove. The cut length of the waterstop is 200mm to 300mm longer than the length of the waterstop installation groove so as to form an overlap at both ends of the waterstop installation groove. S32, apply adhesive evenly to the bottom and both sides of the waterstop, wherein the adhesive is a neoprene rubber adhesive or a polyurethane adhesive. S33, Place the waterstop with the adhesive applied into the waterstop installation groove, so that the center line of the waterstop coincides with the center line of the construction joint, with a deviation not exceeding 5mm.

[0049] Specifically, the waterstop is either a rubber or plastic waterstop, with a cross-sectional shape that is embedded, externally attached, or composite. It should be noted that the waterstop's cut length is 200mm to 300mm longer than the installation groove length, creating an overlap at both ends of the groove. This overlap connects the waterstop to adjacent installation sections, preventing uncovered seepage gaps at the joints during segmented installation. Adhesive is applied to the bottom and sides of the waterstop to ensure initial adhesion to the groove bottom and walls after placement, preventing slippage before grouting. The deviation between the waterstop's centerline and the construction joint's centerline should not exceed 5mm, ensuring the waterstop is centered, the grouting gaps on both sides are symmetrical, and the grout is evenly filled.

[0050] Through the above technical solution, this application uses the cutting, gluing and centering embedding of the waterstop as positioning steps before grouting, so that the waterstop is in the correct position of centering and initial adhesion before the start of pressure grouting, and the grouting gaps on both sides are symmetrically distributed, creating conditions for uniform grouting and symmetrical bonding.

[0051] In an embodiment of the present invention, the step of embedding the waterstop strip into the waterstop strip mounting groove further includes: S34. Before embedding the waterstop into the waterstop installation groove, a layer of water-swellable putty strip is laid at the bottom of the waterstop installation groove. The width of the water-swellable putty strip is equal to the bottom width of the waterstop installation groove, and the thickness of the water-swellable putty strip is 5mm to 10mm.

[0052] Specifically, when the waterstop is a water-swellable rubber waterstop, its expansion rate is 200% to 400%. After contact with water, its volume expands, compressing the grout in the trench wall and grouting gap, further enhancing the sealing effect. It should be noted that a water-swellable putty strip with a width equal to the trench bottom width and a thickness of 5mm to 10mm is laid at the bottom of the trench. This allows the interface between the bottom surface of the waterstop and the trench bottom to receive continuous expansion pressure after contact with water, sealing any tiny seepage channels that may exist between the bottom surface of the waterstop and the trench bottom. Together with the water-sealing grout on both sides, this forms a three-sided seal at the bottom and both sides.

[0053] Through the above technical solution, this application combines water-swellable putty strips with water-swellable rubber waterstops to form a sealing interface on the bottom surface of the waterstop that continuously expands with the contact with water. This compensates for the deficiency that the grout cannot adaptively adjust to the micro-deformation of the structure after curing, and further improves the long-term sealing reliability of the waterstop with post-installation.

[0054] In an embodiment of the present invention, the step of pressurizing and injecting water-stopping and sealing grout into the grouting gap through the grouting pipe includes: S41, a grouting pipe is arranged every 300mm to 500mm on both sides of the waterstop installation groove. The grouting pipe is a metal pipe or a rigid plastic pipe. The inner diameter of the grouting pipe is 8mm to 12mm. One end of the grouting pipe is inserted into the grouting gap, and the other end extends out of the upper surface of the first layer of concrete structure. S42, Prepare the water-stop sealing grout, wherein the water-stop sealing grout is a water-swellable polyurethane grout or an epoxy resin grout, and the initial setting time of the water-stop sealing grout is 30 min to 90 min. S43, starting from one end of the construction joint, the water-stop sealing grout is injected into the grouting gap sequentially through each of the grouting pipes, with an injection pressure of 0.3MPa~0.6MPa. When grout overflows from an adjacent grouting pipe, the injection of the current grouting pipe is stopped and the grouting pipe is sealed.

[0055] Specifically, the grouting pipes are staggered along both sides of the installation groove, with a spacing of 300mm to 500mm, ensuring that the flow path of the grout within the grouting gaps evenly covers the entire length of the groove. It should be noted that the water-swellable polyurethane grout or epoxy resin grout with an initial setting time of 30min to 90min is selected. This ensures that the grout has sufficient time to flow and fill the gaps under grouting pressure, and also allows it to cure and gain strength promptly after filling. Grouting begins sequentially from one end of the construction joint, with the grout advancing from the injection end to the far end, gradually squeezing out air from the gaps. Grout emerging from adjacent grouting pipes is used as a criterion for determining whether that section of the gap is filled. The current grouting pipe is then sealed, ensuring that there are no empty sections or residual air bubbles along the length of the groove. The injection pressure of 0.3MPa to 0.6MPa overcomes the gap resistance, allowing the grout to fully penetrate the micropores of the groove wall concrete, without damaging the groove wall or lifting the waterstop due to excessive pressure.

[0056] Through the above technical solution, this application uses the pressure grouting process of "fixed-distance pipe laying, quantitative preparation, sequential grouting, and grout overflow criterion" to change the fixing method of the waterstop from the passive wrapping during concrete pouring to the active filling of grout under pressure. The density of the grouting gap is measured by grout overflow as an observable quantitative criterion, which completely eliminates the seepage channels formed by air bubbles and voids at the interface of the pre-embedded waterstop.

[0057] In an embodiment of the present invention, the step of injecting the water-stopping sealant into the grouting gap sequentially through each of the grouting pipes, starting from one end of the construction joint, further includes: S44. During the grouting process, a continuous weight is applied to the top surface of the waterstop, with a weight pressure of 0.01MPa to 0.03MPa, to prevent the waterstop from floating or shifting under the grouting pressure.

[0058] Specifically, the grouting pressure acts on both sides and the bottom of the waterstop, tending to cause the waterstop to float upwards and be pushed out of the installation groove. It should be noted that a continuous weight of 0.01MPa to 0.03MPa is applied to the top surface of the waterstop to keep the weight and grouting pressure balanced on the waterstop. The waterstop remains in contact with the bottom of the groove during the grouting process, and the width of the grouting gap does not change due to the waterstop floating upwards, resulting in uniform grout filling thickness. If the weight is too small, it will not be able to balance the grouting pressure; if it is too large, it will damage the waterstop or hinder the flow of grout on the bottom surface of the waterstop.

[0059] Through the above technical solution, this application applies a quantitative weight to the waterstop during the pressure grouting process, which eliminates the floating deformation of the waterstop caused by the grouting pressure, ensures the uniformity of the grout filling thickness and the stability of the waterstop position, and enables the pressure grouting process to be completed under the condition that the geometric boundaries remain unchanged.

[0060] In an embodiment of the present invention, after the step of injecting the water-stop sealing grout into the grouting gap sequentially through each of the grouting pipes starting from one end of the construction joint, the method for post-installation of the waterstop at the concrete construction joint further includes: S45, after the initial setting of the water-stop sealing grout, supplementary grouting is performed on the grouting gap. The pressure of the supplementary grouting is 0.1MPa~0.2MPa, and the amount of grout used for supplementary grouting is 10%~20% of the amount of grout used in the initial grouting. S46, after the water-stop sealing grout has completely cured, cut off the end of the grouting pipe that extends out of the upper surface of the first layer of concrete structure, and seal the cut of the grouting pipe with sealant.

[0061] Specifically, the sealing grout undergoes volume shrinkage during initial setting and curing, which may create micro-shrinkage cracks in the gaps filled during the initial grouting. It should be noted that after the grout has initially set, supplementary grouting should be performed at a low pressure of 0.1MPa to 0.2MPa, with the supplementary grout amount being 10% to 20% of the initial grout volume. This ensures that the grout fills the gaps formed by the initial shrinkage without causing the already set grout to expand due to excessive pressure. After the grout has completely cured, the protruding end of the grouting pipe should be cut off and the cut sealed with sealant to prevent the grouting pipe from becoming a seepage channel penetrating the upper surface. This also ensures a smooth surface at the construction joint, facilitating subsequent construction of the protective and leveling layers.

[0062] Through the above technical solution, this application compensates for the initial setting shrinkage of the grout by completing the finishing process of "low-pressure grouting after initial setting and sealing the pipe after curing", eliminating the potential water seepage hazards left by the grouting pipe and ensuring that the sealing system formed by pressure grouting is completely closed.

[0063] In an embodiment of the present invention, after the waterstop is fixed in the waterstop installation groove by the waterstop sealing slurry, the post-installation method of the waterstop at the concrete construction joint further includes: S51, a protective layer is covered above the waterstop strip. The protective layer is a cement mortar protective layer or a fine stone concrete protective layer, and the thickness of the protective layer is 20mm to 30mm. S52, a layer of wire mesh or alkali-resistant fiberglass mesh is laid inside the protective layer, and the overlap width of the wire mesh or alkali-resistant fiberglass mesh is 100mm to 150mm. S53, making the surface of the protective layer flush with or slightly lower than the upper surface of the first layer of concrete structure.

[0064] Specifically, the top surface of the waterstop is 10mm to 20mm lower than the upper surface of the first layer of concrete, providing space for the protective layer. It should be noted that the protective layer covers the waterstop to isolate it from subsequent trampling, mechanical impacts, and sunlight during construction, preventing damage and aging of the waterstop before the second layer of concrete is poured. Steel wire mesh or alkali-resistant fiberglass mesh is laid inside the protective layer, with the overlap width controlled at 100mm to 150mm, to inhibit shrinkage cracking of the mortar or concrete protective layer and prevent cracks from penetrating to the waterstop. The surface of the protective layer is flush with or slightly lower than the upper surface to avoid forming protrusions at construction joints that would weaken the compactness of the second layer of concrete at that location.

[0065] Through the above technical solution, this application utilizes the reserved height difference on the top surface of the waterstop to set a protective layer with crack-resistant mesh, so that the waterstop is always in a protected state during the time window between the completion of installation and the pouring of the second layer, while ensuring the flatness of the construction joint surface, thus taking into account both protection and bonding.

[0066] In an embodiment of the present invention, before the second layer of concrete structure is poured, the method for post-installation of the waterstop at the concrete construction joint further includes: S61, an interface treatment agent is applied to both sides of the waterstop installation groove. The interface treatment agent is a cement-based interface treatment agent or a polymer emulsion interface treatment agent. S62, a cement mortar leveling layer is laid on the upper surface of the first layer of concrete structure. The thickness of the cement mortar leveling layer is 10mm to 20mm. The cement mortar leveling layer covers the surface area of ​​the construction joint where the waterstop installation groove is located, so as to ensure that the bonding surface between the second layer of concrete structure and the first layer of concrete structure is flat.

[0067] Specifically, before pouring the second layer of concrete, the surface of the construction joint and the protective layer may be uneven and contaminated. It should be noted that applying an interface treatment agent to both sides of the installation groove enhances the bond between the second and first layers of concrete at the interface. A 10mm–20mm thick cement mortar leveling layer is then laid to cover the construction joint surface area where the installation groove is located, ensuring a smooth interface between the new and old concrete. This prevents voids and segregation in this area during the vibration of the second layer of concrete, and ensures a dense bond between the waterstop and the concrete on both sides.

[0068] Through the above technical solution, this application completes interface treatment and leveling before the second layer of concrete is poured, so that the two bonding interfaces between the post-installed waterstop and the first and second poured concrete are both dense and reliable, and the waterstop is continuously and completely sealed at the construction joint.

[0069] This construction method employs a post-installation process of "grooving, cleaning, embedding, and pressure grouting," shifting the installation of the waterstop from before to after pouring concrete. This allows for precise positioning of the waterstop on the hardened construction joint surface, and pressure grouting ensures a tight bond with the groove walls and bottom. Furthermore, this method utilizes a grooving sequence of cutting edges before chiseling, weighted anti-floating measures, supplementary grouting, protective layer coverage, and interface leveling to guarantee the stability of the waterstop's position and the integrity of the sealing system. This method solves the problems of waterstop misalignment and poor bonding with concrete that lead to construction joint leakage, offering advantages such as accurate waterstop positioning, tight bonding, and reliable and durable water-stopping effect.

[0070] The following example will provide a more detailed explanation of the above technical solution: In a certain underground water tank project, the base slab was constructed using C30 concrete in layers. The first layer of concrete was 1.2 meters thick, and the construction joint extended longitudinally along the base slab for 30 meters. When the first layer of concrete was poured and reached 75% of its design strength, the surface slurry of the construction joint had hardened but was not completely dry. Subsequently, the waterstop was installed in a post-installation manner.

[0071] First, lay out the boundary lines of the waterstop installation trench along both sides of the construction joint. The distance between the boundary line and the center line of the construction joint is half the width of the waterstop plus 25 mm. Cut downwards along the boundary line to form a boundary slit 40 mm deep. Then, chisel away concrete in sections between the boundary slits on both sides to a depth of 40 mm, without damaging the bottom slab reinforcement during the chiseling process. Trim the trench walls and bottom. The measured flatness deviation of the trench bottom is 2 mm / 2 meters. The trench width is 1.3 times the width of the waterstop.

[0072] Next, remove the laitance, loose particles, and accumulated water from the trench. After the trench walls and bottom are dry, apply a polyurethane primer evenly. Select an embedded rubber waterstop, cut it to 250 mm longer than the actual length of the installation trench. Apply neoprene rubber adhesive to the bottom and both sides of the waterstop before placing it in the trench. The actual deviation between the center line of the waterstop and the center line of the construction joint is 3 mm. The top surface of the waterstop is 15 mm lower than the top surface of the first layer of concrete, forming a grouting gap of about 12 mm on each side.

[0073] Next, rigid plastic grouting pipes with an inner diameter of 10 mm are staggered every 400 mm on both sides of the installation groove. One end of the grouting pipe is inserted into the grouting gap, and the other end extends out of the upper surface. A water-swellable polyurethane grout with an initial setting time of 60 minutes is prepared. A continuous pressure of 0.02 MPa is applied to the top surface of the waterstop. Grouting is started sequentially from one end of the construction joint, with an injection pressure of 0.4 MPa. Grouting is stopped and the current grouting pipe is sealed after grout emerges from an adjacent grouting pipe. After the grout has initially set, additional grouting is performed at a pressure of 0.15 MPa, with the additional grout amount being 15% of the initial grouting volume. After the grout has completely cured, the protruding end of the grouting pipe is cut off, and the cut is sealed with sealant.

[0074] Then, a 25 mm thick cement mortar protective layer is placed over the waterstop, and an alkali-resistant fiberglass mesh is laid inside the protective layer with an overlap width of 120 mm. The surface of the protective layer is flush with the surface of the first layer of concrete.

[0075] Finally, before pouring the second layer of concrete, apply a polymer emulsion interface treatment agent to both sides of the installation groove, and lay a 15 mm thick cement mortar leveling layer to cover the surface area of ​​the construction joint, and then pour the second layer of concrete.

[0076] The project was constructed using this method, and the water storage test passed on the first attempt. No leakage occurred at the construction joints during the operation period, verifying the reliability and long-term effectiveness of this method.

[0077] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of protection of the present invention. Any equivalent structural transformations made based on the technical concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A method for post-installation of a waterstop at a concrete construction joint, used to install a waterstop at the construction joint between a first layer of concrete structure and a second layer of concrete structure, wherein the waterstop is embedded in a waterstop installation groove formed on the surface of the construction joint of the first layer of concrete structure, and a grouting gap is reserved between the two sides of the waterstop and the sidewall of the waterstop installation groove, and a grouting pipe is embedded in the grouting gap, characterized in that... The method for post-installation of the waterstop at the concrete construction joint includes: A waterstop installation groove is opened on the surface of the construction joint of the first layer of concrete structure that has been poured. The waterstop installation groove is continuously arranged along the extension direction of the construction joint. The cross-section of the waterstop installation groove is an inverted trapezoid or a rectangle. The depth of the waterstop installation groove is 30mm to 50mm. The width of the waterstop installation groove is 1.2 to 1.5 times the width of the waterstop. The walls and bottom of the waterstop installation groove are cleaned and dried to remove laitance, loose particles and water, and a base treatment agent is applied to the walls and bottom of the waterstop installation groove. The waterstop is embedded in the waterstop installation groove. The top surface of the waterstop is lower than the upper surface of the first layer of concrete structure by 10mm to 20mm. Grouting gaps are reserved between the two sides of the waterstop and the side wall of the waterstop installation groove. Water-stop sealing grout is injected into the grouting gap through the grouting pipe. Under pressure, the water-stop sealing grout fills the grouting gap and bonds and fixes the waterstop strip to the waterstop strip installation groove. The injection pressure is 0.3MPa~0.6MPa.

2. The method for post-installation of waterstop at concrete construction joints as described in claim 1, characterized in that, The step of creating a waterstop installation groove on the surface of the construction joint of the first layer of concrete structure that has already been poured includes: Lay out the boundary lines of the waterstop installation groove along both sides of the construction joint. The distance between the boundary lines and the center line of the construction joint is half the width of the waterstop plus 20mm to 30mm. The waterstop installation groove is excavated by first cutting the boundary and then chiseling away the groove body. First, a boundary cut with a depth of 30mm to 50mm is cut downward along the boundary line. Then, the concrete is chiseled away in sections between the boundary cuts on both sides to a depth of 30mm to 50mm. During the chiseling, the depth of each chiseling is controlled and damage to the steel bars in the first layer of concrete structure is avoided. The groove walls and bottom after chiseling are repaired to make the cross-sectional shape of the waterstop installation groove regular and the flatness deviation of the groove bottom not exceed 3mm / 2m.

3. The method for post-installation of waterstop at concrete construction joints as described in claim 1, characterized in that, The waterstop is a rubber waterstop or a plastic waterstop, and the cross-sectional shape of the waterstop is embedded, externally attached, or composite. The step of embedding the waterstop strip into the waterstop strip mounting groove includes: The waterstop is cut according to the actual length of the waterstop installation groove. The cut length of the waterstop is 200mm to 300mm longer than the length of the waterstop installation groove so that an overlap is formed at both ends of the waterstop installation groove. An adhesive is evenly applied to the bottom and both sides of the waterstop. The adhesive is a neoprene rubber adhesive or a polyurethane adhesive. Place the waterstop coated with the adhesive into the waterstop installation groove, so that the center line of the waterstop coincides with the center line of the construction joint, with a deviation not exceeding 5mm.

4. The method for post-installation of waterstop at concrete construction joints as described in claim 1, characterized in that, The step of injecting water-stopping and sealing grout into the grouting gap through the grouting pipe includes: A grouting pipe is arranged every 300mm to 500mm on both sides of the waterstop installation groove. The grouting pipe is a metal pipe or a rigid plastic pipe. The inner diameter of the grouting pipe is 8mm to 12mm. One end of the grouting pipe is inserted into the grouting gap, and the other end extends out of the upper surface of the first layer of concrete structure. The water-stop sealing grout is prepared as a water-swellable polyurethane grout or an epoxy resin grout, and the initial setting time of the water-stop sealing grout is 30 min to 90 min. Starting from one end of the construction joint, the water-stop sealing grout is injected into the grouting gap sequentially through each of the grouting pipes at an injection pressure of 0.3MPa to 0.6MPa. When grout overflows from an adjacent grouting pipe, the injection of the current grouting pipe is stopped and the grouting pipe is sealed.

5. The method for post-installation of waterstop at concrete construction joints as described in claim 4, characterized in that, Following the step of injecting the water-stop sealing grout into the grouting gap sequentially through each of the grouting pipes starting from one end of the construction joint, the post-installation method of the waterstop at the concrete construction joint further includes: After the initial setting of the water-stop sealing grout, supplementary grouting is performed on the grouting gap. The pressure of the supplementary grouting is 0.1MPa~0.2MPa, and the amount of grout used for supplementary grouting is 10%~20% of the amount of grout used in the initial grouting. After the water-stop sealing grout has fully cured, the end of the grouting pipe extending out of the upper surface of the first layer of concrete structure is cut off, and the cut of the grouting pipe is sealed with sealant.

6. The method for post-installation of waterstop at concrete construction joints as described in claim 1, characterized in that, After the waterstop is fixed in the waterstop installation groove by the waterstop sealing grout, the post-installation method of the waterstop at the concrete construction joint further includes: A protective layer is placed over the waterstop, which is a cement mortar protective layer or a fine stone concrete protective layer, and the thickness of the protective layer is 20mm to 30mm. A layer of wire mesh or alkali-resistant fiberglass mesh is laid inside the protective layer, and the overlap width of the wire mesh or alkali-resistant fiberglass mesh is 100mm to 150mm. The surface of the protective layer is flush with or slightly lower than the upper surface of the first layer of concrete structure.

7. The method for post-installation of waterstop at concrete construction joints as described in claim 2, characterized in that, The timing for opening the waterstop installation groove is before the first layer of concrete structure reaches more than 70% of the design strength and before the laitance layer on the surface of the construction joint has hardened but not completely dried. If the surface of the construction joint is completely dry, the surface of the construction joint should be moistened with water before opening the installation groove for the waterstop, so that the moisture content of the surface of the construction joint reaches 8% to 12%.

8. The method for post-installation of waterstop at concrete construction joints as described in claim 3, characterized in that, The waterstop is a water-swellable rubber waterstop, and the expansion rate of the water-swellable rubber waterstop is 200% to 400%. Before embedding the waterstop into the waterstop installation groove, a layer of water-swellable putty strip is laid at the bottom of the waterstop installation groove. The width of the water-swellable putty strip is equal to the bottom width of the waterstop installation groove, and the thickness of the water-swellable putty strip is 5mm to 10mm.

9. The method for post-installation of waterstop at concrete construction joints as described in claim 4, characterized in that, During the process of sequentially injecting the water-stop sealing grout into the grouting gap through each of the grouting pipes, a continuous weight is applied to the top surface of the waterstop, with a weight pressure of 0.01MPa to 0.03MPa, to prevent the waterstop from floating or shifting under the grouting pressure.

10. The method for post-installation of waterstop at concrete construction joints as described in claim 1, characterized in that, Before the second layer of concrete structure is poured, the method for post-installing the waterstop at the concrete construction joint also includes: An interface treatment agent is applied to both sides of the waterstop installation groove. The interface treatment agent is a cement-based interface treatment agent or a polymer emulsion interface treatment agent. A cement mortar leveling layer is laid on the upper surface of the first layer of concrete structure. The thickness of the cement mortar leveling layer is 10mm to 20mm. The cement mortar leveling layer covers the surface area of ​​the construction joint where the waterstop installation groove is located, so as to ensure that the bonding surface between the second layer of concrete structure and the first layer of concrete structure is flat.

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