C40 Grouting Material C60 High-Strength Non-Shrink Grouting Material
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Where to Buy Non-Shrink Grout C40 Grouting Material in Nanchang, Jiangxi
I. Definition and Function of Secondary Grouting
(I) Definition of Secondary Grouting;
During foundation pouring, holes for anchor bolts are pre-reserved (i.e., reserved holes). During equipment installation, anchor bolts are placed into these holes, and then concrete or cement mortar is poured to fix the anchor bolts. This method is called secondary grouting.
(II) Function of Secondary Grouting;
After the equipment is inspected and adjusted to meet standards, secondary grouting should be carried out as soon as possible. The secondary grouting layer primarily prevents shim loosening. The concrete for secondary grouting is the same as the foundation concrete, but the size of the aggregate should be appropriately selected based on the thickness of the secondary grouting layer. To fill the narrow space under the equipment base, smaller aggregate is typically used compared to the foundation. Care should be taken during pouring to avoid disturbing the shims and equipment.
(III) Pouring Mortar;
Once each piece of equipment is installed, passes strict inspection to meet installation technical standards, and is approved by relevant units, grouting can proceed. Reinforced concrete slab bridges are the most widely used superstructure form for small and medium-span highway bridges. Summarizing existing tests and engineering application research, it can be seen that carbon fiber sheet reinforcement for solid slabs and T-beams with rectangular sections has been studied more, while its application for hollow slab beams is relatively less. This study focuses on hollow and solid slab beams as analytical subjects, collecting calculation methods and formulas from domestic and international highway bridge reinforcement specifications and related industry standards. Considering the existing achievements in bridge reinforcement work by design, research, and construction units in China, as well as referenced standards, three specifications or codes for carbon fiber paste reinforcement calculation formulas were selected for comparative analysis. Grouting involves filling the gaps between the equipment base and the foundation surface, as well as the anchor bolt holes, with concrete or mortar. One function is to fix the shims (the movable parts of adjustable shims cannot be fixed by pouring), and another is to transfer some equipment load to the foundation.
(IV) Key Points of Grouting Operation;
(1) Before grouting, rinse the grouting area with water to ensure the new concrete (or mortar) bonds firmly with the original concrete.
(2) Grouting generally uses fine aggregate concrete (or cement mortar Nitric acid solution with pH=1 erodes mortar faster than sulfuric acid in the early stages. Sulfate ions of different concentrations in acidic solutions affect the matrix differently. In this experiment, with solution pH=1 and SO₄²⁻ concentration of 4800 mg/L, SO₄²⁻ does not accelerate the corrosion rate; instead, the accumulation of dihydrate gypsum on the surface provides temporary protection, with acidic erosion being dominant. At high SO₄²⁻ concentrations (about 28800 mg/L), H⁺ and SO₄²⁻ jointly accelerate mortar deterioration. Therefore, when conducting accelerated tests, the sulfate ion concentration in the erosion solution must be carefully selected.), with a grade at least one level higher than the foundation concrete and not lower than grade 150. Aggregate size should be selected based on gap size, typically 5–15 mm, using grade 400 or 500 cement.;
(3It involves continuously applying a layer of CFRP sheets (or similar plates) along both sides of the beam web and the bottom surface over a certain longitudinal length of the reinforced beam, pressing down the longitudinally applied CFRP sheets at the beam bottom to achieve anchoring. To reduce the occurrence of debonding failure, the width, clear spacing, and height of U-wraps within a certain range should be set reasonably. When multiple layers of prestressed carbon fiber fabric are applied, multiple layers of U-wraps should also be applied to enhance the anchoring effect. In Tsinghua University's prestressed CFRP sheet reinforcement tests, U-wraps of certain width, spacing, and layers were arranged along the longitudinal direction of the reinforced beam.) During grouting, an outer formwork should be placed, with its edge generally no less than 60 mm from the equipment base edge. If the entire area under the equipment base does not need to be fully grouted and the grouting layer must bear equipment load, inner formwork should also be placed to ensure the quality of the grouting layer. The distance from the inner formwork to the outer edge of the equipment base should be greater than 100 mm and not less than the width of the base bottom. The height of the grouting layer should be higher than the base bottom outside the base. The upper surface of the grouting layer should have a slight slope (sloping outward) to prevent oil and water from flowing into the equipment base.After concrete cracking, the local state of bond stress changes. At the crack, a slight debonding occurs at the interface between the carbon fiber sheet and the concrete. The cracked concrete no longer bears tension (bending moment), while the tension borne by the carbon fiber sheet (bending moment) increases suddenly. Due to the bonding between the carbon fiber sheet and concrete working together, the load (bending moment) borne by the concrete gradually accumulates and increases with distance along the longitudinal direction on both sides of the crack, while the load (bending moment) borne by the carbon fiber sheet gradually decreases to the level before concrete cracking. The accumulation of bond stress over a certain length can cause the tensile stress in the concrete to reach its tensile strength, leading to new cracks. Since carbon fiber sheets constrain concrete deformation in both longitudinal and transverse directions, the crack width in carbon fiber-reinforced members is smaller than in ordinary concrete beams, and the crack spacing is also smaller. The local bond stress distribution is generally similar. When analyzing failure modes, we mainly consider the local bond stress at the ends of the carbon fiber sheets and at the cracks. When the peak local bond stress (or average bond stress) exceeds the bond strength between the carbon fiber sheet and concrete or the concrete's tensile (shear) strength, debonding occurs.;
(4) Grouting work must be continuous without interruption and completed in one pour. Concrete or mortar should be compacted in layers. During compaction, avoid concentrating on one area and ensure that anchor bolts remain perpendicular to the installation plane. Otherwise, it may not only cause installation difficulties but also affect equipment precision.;
(5) After grouting, water curing should be performed. Curing The mechanism of early cracking during concrete construction is related to the types and causes of early cracks. Different early cracks have different cracking mechanisms at different research scales. Initial microcracks caused by internal stress, plastic shrinkage, and settlement shrinkage are suitable for analysis at the meso-scale rather than the macro-scale. time should be no less than one week; the frequency of watering should maintain sufficiently moist conditions for the concrete. Anchor bolts should not be tightened until the concrete curing reaches at least 70% of its strength. The time required for concrete to reach 70% strength depends on temperature and can be referenced in the table below.
(V) Grouting Precautions;
(1) After equipment alignment and initial leveling, grouting must be done promptly. If more than 48 hours pass, recheck the equipment's elevation, center, and levelness.;
(2) The grouting layer thickness should not be less than 25 mm to effectively fix shims or prevent oil and water ingress.
(3) Generally, the height of secondary grouting should at least cover the shims but not exceed the nuts of the anchor bolts.
(4) For fixed anchor bolts, the bolt sleeves must be completely filled with grout during secondary grouting. For movable anchor bolts, do not fill the bolt sleeves with mortar during secondary grouting.
(5) When high contact is required between the grouting layer and the equipment base bottom, use concrete (or cement mortar) mixed with expansive cement.;
(6) Be very careful when placing formwork to avoid disturbing the equipment.;
(7) To ensure good contact between shims and the equipment base bottom and grouting layer, the pressure grouting method can be used.
For details, please consult Bory Business Manager. Detailed answers available.
| Industry Category | Construction-Real-Estate |
|---|---|
| Product Category | |
| Brand: | 江西宝和 |
| Spec: | C40C50C60C80C100 |
| Stock: | 600 |
| Manufacturer: | |
| Origin: | China / Jiangxi / Nanchangshi |
