Repair treatment of cracks in old water conservancy dams. Surface carbonization enhances strength, etc. It has been applied to the Three Gorges Dam with remarkable results. The quality is extraordinary. Deep penetration crystalline type. Foreign imports
United States CO-MA-SEAL ® Brief Introduction of Penetrating Crystalline Concrete Protective Agent CM
United States CO-MA-SEAL ® Concrete protective agent CM (hereinafter referred to as CM) is a water-based permeable crystalline type. Its protective mechanism is to produce chemical reaction with active ingredients such as free alkali in the concrete, generate stable dendritic crystal colloid, effectively block the micro cracks and capillary voids in the concrete, so that the concrete structure has good protective function and better compactness and compressive strength. At the same time, it can effectively prevent the erosion and damage of acid-base substances, oil stains, seaweed, salt, etc. to the concrete, and can also improve the protection ability of concrete against freeze-thaw, carbonization, and scouring by improving the compactness and impermeability of concrete.
1、 Introduction: According to the inspection of the National Laboratory of the United States, the interior of a concrete contains 361 times the surface area of alkali. Therefore, CM, which penetrates into the concrete and chemically reacts with alkali, is not only effective but also becomes a structural part of concrete. It is not just a surface material. With CM protective material, it will react with alkali without gasification and deterioration, thus forming a long-term protective, anti-corrosion, sealing and silicified layer. It only needs to be used once, because it is unlike other The material is also worn and can penetrate 20-30mm below the concrete surface.
External substances such as moss, acid, alkali, oil, salt, sewage and other harmful substances can damage concrete, and water is no exception. When immersed in concrete, various damages will occur, greatly shortening the life of concrete structures. However, the use of CM is helpful to prevent such damage. Because of the chemical reaction with the concrete, a gel is formed. The capillary attraction and wetting force this gel to enter the voids and channels under the concrete surface. CM floats along the capillary pores and channels of the concrete filled with free alkali and water vapor. This product has affinity for alkali and moisture. When drifting, it will encounter more alkali and produce more jelly. This process itself continues until the concrete is sealed for a long time, but it makes the concrete "breathe".
2、 Relevant executive standards:
SL352-2006 Test Specification for Hydraulic Concrete, etc
"Compressive strength", "core strength test", "split flexural strength test", "impermeability test", "carbonization test", "freeze-thaw resistance test", etc. in SD105-82 Hydraulic Concrete Test Specification
CECS 195-2006 Polymer cement Technical Specification for Application of Permeable Crystalline Waterproof Materials
DBJ01-54-2001 Permeable Waterproof coating Quality Inspection Standard
GB 50208-2008 Code for Quality Acceptance of Underground Waterproof Engineering
GB/T 17219-1998 Safety Evaluation Indicators for Drinking Water Transmission and Distribution Equipment and Maintenance Materials
GB/T50082-2009 Test Method for Long term Performance and Durability of Ordinary Concrete/(GBJ82-85)
JTJ 275-2000 Technical Code for Anticorrosion of Concrete Structures in Port Engineering
3、 Parameters:
PH value: 11 ± 1;
Appearance: colorless, tasteless and harmless;
Density: 1.07 ± 0.05;
Flammability: non combustible;
Freezing point: 0 °;
Boiling point: 100 °;
Impermeability grade: ≥ P11 (refer to building materials standards);
Compressive strength: ≥ high standard (refer to building materials standard);
48h water absorption: ≤ 65%;
Anti permeability pressure ratio: ≥ 200% (refer to building materials standards);
Frost resistance: 20 °~- 20 °, 15 times of surface without pulverization and cracks;
Heat resistance: 80 °, 72 hours, no powdering and cracks on the surface;
Alkali resistance: after soaking in saturated calcium hydroxide solution for 168 hours, the surface is free of pulverization and cracks;
Acid resistance: Soak in 1% hydrochloric acid solution for 168 hours, and the surface is free of pulverization and cracks;
Corrosion of reinforcement: no corrosion;
Chloride ion permeability resistance: ≤ 1000 C (refer to JTJ 275-2000 Specification for Concrete Corrosion Protection of Port Engineering);
Shelf life: more than 5 years;
Environmental protection: meet the health and safety test standards for drinking water transmission and distribution equipment.
4、 Introduction to the main advantages of CM
a . It can withstand strong water pressure for a long time
Adopt all standards AS TM E-5 14 Water Permeance impermeability, "Permeability Performance Standard CRD-C48-73" of the US Army * * * Cheng Corps, and relevant Chinese standards have been tested. They all have very high impermeability and impermeability pressure ratio. Moreover, the protective layer and base layer can be combined through osmotic crystallization. Unlike traditional coating protective materials, the adhesive force will be reduced and gradually lost after soaking in water, As a result, its protective effect is affected. Therefore, CTI permeable crystalline products are very suitable for long-term water soaked projects, such as underground works, dams and other projects. They are high-quality materials for waterproof protection of concrete structures. American CTI osmotic crystallization products were adopted and recognized by the world's water conservancy project - the Three Gorges Project. In 2013, they also participated in the domestic water conservancy project - the source project of the South to North Water Diversion Project - the seepage resistance and abrasion resistance project of Danjiangkou Reservoir. These are very convincing cases of American CTI osmotic crystallization products that can withstand long-term seepage and strong water pressure after construction.
b . The protective effect is long-term
The active substance of CM is an inorganic substance. It depends on chemical reaction to generate a unique dendritic silica crystal to grow in the concrete capillary holes on the construction surface, so as to make the concrete protective performance. That is to say, it realizes the structural self-protection of the protection layer and the construction base plane, and the silica crystal embedded in the concrete capillary holes belongs to the same kind of material as the concrete, The rate of thermal expansion and contraction is the same as that of concrete, which will not peel, peel, age or deteriorate, and the coating is not afraid of puncture, so its function is the same as that of concrete.
c Self repair ability with advantages
CM is a chemical reaction product. At the beginning, the chemical reaction only occurs on the surface or adjacent parts of the concrete. Later, it will gradually penetrate into the concrete components. Because of the unique catalyst in CM, it will be activated when encountering water, prompting the cement to produce new crystals. Cracks smaller than 0.4mm on the concrete components can be filled by crystals and sealed by itself, That is to say, the treated concrete structure will produce new tiny cracks due to vibration or other reasons several years later. Once there is water leakage, new crystals will be generated to block the water, so its self repair ability is unique. This repair capability (or secondary impermeability according to Chinese specifications) is more practical than traditional adhesive protective materials.
d CM is a harmless and pollution-free product, even the VOC of volatile agricultural production system is zero, which is truly green and environmentally friendly
CM has been approved by the Ministry of Health, Health and Environmental Protection of many countries in the world door Approved by the National Building Materials Testing Center, it has passed the national standard GB/T17219-1998 Safety Evaluation Standard for Drinking Water, Water Transmission and Distribution Equipment and Protective Materials. Volatile agricultural production system substances are zero or even lower than the surface of apples sold on the market, which has no impact on human body and the environment. The Three Gorges Dam The source project of the South to North Water Diversion Project - Danjiangkou Dam has been fully verified for its safe use.
e CM is inorganic, so it has strong weather resistance, temperature resistance, humidity resistance, ultraviolet resistance, radiation resistance and oxidation resistance
Compared with the traditional coating protective materials belonging to the agricultural production system, CM, an inorganic product, is just like stone and plastic. Stone is not afraid of outdoor wind, rain, cold and hot weather, while plastic becomes brittle, discolored and broken after being placed for several months. Therefore, an outstanding advantage of inorganic products is also reflected in weather resistance, which is very practical in practical application, It not only adapts to the cold zone climate but also to the tropical climate, especially in the concrete structure with large temperature difference change and large influence of ultraviolet ray or photothermal aging, not only has obvious performance advantages, but also has the same service life as the concrete structure, which reduces the repeated maintenance in the later period and meets the requirements of the conservation oriented society.
f CM can enhance the strength of concrete, prevent chemical corrosion, relieve alkali aggregate reaction, prevent the damage of freeze-thaw cycle to concrete, and protect reinforcement
According to the American ASTM C-39 "Compressive Strength Test" in 1981, the compressive strength of the sample treated with CM is more than 20% higher than that of the sample untreated. According to ASTM C267-77 "Impedance test of mortar to chemical substances", CM is not corroded by chemical substances (including weak acid substances, chlorides and alkaline substances) in a wide range. The tests completed according to the American "ASTM-C672-76 Standard Test Method for Resistance to Stripping of Concrete Surface Exposed to Deicing Chemicals" and the American Department of Transportation "Method for Evaluating Concrete Surface Coatings" show that CM not only protects but also prevents the intrusion of chemicals, salts and other harmful substances. Cracks smaller than 0.4mm on concrete components can be filled and sealed by crystals, so it can improve the protection of concrete on reinforcement, and prevent spalling, weathering and other damage caused by freeze-thaw cycles.
g CM can improve the concrete quality of the construction formation surface in addition to protecting against seepage. The construction can also be synchronized with the construction of the concrete structure. Other coatings can be accepted after treatment, without affecting the subsequent construction
When CM is applied to new or under construction concrete structures, it can be used synchronously with concrete pouring, and can accelerate cement hydration and crystallization, improve concrete strength, reduce or avoid cracks in concrete, shorten the curing period, thus saving the construction period. The surface of treated concrete structures can be completely coated with coating materials such as coating type protection, It can also build a protection system together with other protective materials.
h CM has high cost performance ratio, simple construction method and is less vulnerable to human operation
Compared with the traditional coating type protection, CTI's permeable crystalline products are more convenient in construction. No interface coating or surface leveling work is required in the construction, and no hot melting or cold sticking splicing is required in the operation. The integrity is good, and seamless splicing can be achieved.
5、 Some dam engineering cases at home and abroad (all with supporting materials)
Three Gorges Dam. It stands out from the competition of more than 50 products at home and abroad.
Danjiangkou Reservoir of South to North Water Transfer Project
Certificate of Use of Bremerton Port Authority (wharf, seawall, pontoon)
Flood discharge dam and fish ladder reinforcement project of Bonway Dam in Columbia River Gorge, USA
Corps of Engineers certification (dam and reservoir)
6、 Other technical references:
AASHTO - American Highway and Transportation Association
ASTM - American Standard Test for Materials
BSI - British Standards Institute
VDOT - Virginia Department of Transportation
HYD - Hong Kong Highways Department
American Coating Technology Co., Ltd
China Office
