1.0 Brief introduction

Cracks will occur on roadway, bridge, tunnel, dam and other building because building aging (efflorescence, ultraviolet radiation, acid rain action), inappropriate design, improper material usage when changing load, bad construction, asymmetric sinking of base, earthquake, fire etc.
Influence that cracks cause to building is important. With time passing and because of harmful substance inrushing, cracks enlarge and become bad gradually. Then, building' performance of usage will play down and life of service will shorten, Even it will cause collapse of building, and become unsafe.

1.1 Influence that cracks cause to building

Influence that cracks cause to building is divided up five aspects:

1. Influence that cracks cause to rigidity of whole structure
When cracks appear, structure rigidity, shear strength, tension strength and moment strength will lack. Stress will be distributed again, and destroy continually even members will collapse.

2. Rigidity of concrete decrease
Cracks make available section of member damage and stiffness of section lack, so, flection of member increase and the probability of shake failure will enhance. At one time, because structure rigidity reduce, stress will be distributed again that make cracks enlarge and develop continually. When cracks run through members, section rigidity of concrete will be out of action and steel bars will support all loads, and members are in the danger of collapse.

3.Strength of steel bars decrease
Cracks make strength of steel bars decrease, and besides, they make steel bars rust, hydrogenate and embrittle, and decrease grasp force between steel bars and concrete, decrease tension strength of steel bars too. Hydrogenation and embritlement can make ductibility of bars lower and bars have a tendence to be similar with to brittle material, so, it is dangerous that there is a warning before members failure.

4.Water-seal performance reducing
As a result of water-seal performance' falling quickly, acid and alkali stuff corrade into concrete member that make steel bars rust quickly and make concrete acid. So building will be damaged highly.

5.Influence that cracks cause to permanence
Influence that cracks cause to permanence is mainly to make concrete acid quickly and make steel bars rust quickly, and decorated layer and protected layer flake off because concrete have gone moldy by leaking and seeping, then, life of building will become short. So, in order to hold out safety and life of building, we must repair cracks. Reference to standard of Occident, Japan (the below list)

ACI Standard in terms of permanence:

The maximal width of cracks allowed according to demand of perdurability

[AC1224COMMITTEE]

As for structure reinforcement that is operated after repair is not referred in this text.

2.High-pressure injecting method
We should inject material into members with high pressure (20mpa ~ 40mpa) in limited time. The method is suitable to continual wall of the underground, and we may use various materials according to spots.

3.V-Cut cracks repair method
Cut a hole or a V-groove with diamond cut-machine; then, fill it up with elastic paint or epoxy resin; finally, cover the work surface with glass fiber or elastic paint. The method often is used in brick wall，cellularity concrete and dry-shrinking cracks between partition and concrete.

2.0 Introduction on our products series

This chapter' content includes AE150 continual compressive injecting system, AS2000 high-pressure injecting system and V-Cut surface repair system.

2.1 Products series on injecting method of A&GOOD AE150

AE111, AE160, AE150, AE151, AE152, AE153, AC810, AC100

2.1.1 Concrete Adhesive（Sealant）AE111AB (N)Normal (F) Fast Dry

Advantage：

• High adhibition strength --Have a good bond to materials except for PVC
• High strength -- about 5600psi in 8 hours
• No drooping -- can be used on the vertical plane or fall plane

2.1.2 Crack Injection Resin AE160AB
Appropriate to general concrete structure where cracks is not more than 1.5mm.

Advantage:

• Non-shrinking-no chap like cement shrinking
• Well fluidity-can be applied to any cracks and little hole
• Changeless packaging，used conveniently anywhere and anytime
• Low or high pressure injecting method are all able to be well applied
• High adhibition strength
• High strength
• Water-repellent，good permanence，to protect steel bars from corrading

2.1.3 Dual axes continual-pressure injector AE150

AE150 repair method is the best method to repair cracks with injector among all methods of cracks repair in important structures. Its advantages are stated:

• Reagent is filled up well according to graduation against waste of reagent
• Press well, and press according to design with AE153
• The dosage injected can be measure accurately for being checked up
• Replacing injectors easily
• The process of pressing is easy to operate, and only need to hang AE153
• Continual pressure make reagent go deep into minute cracks, and have no fake saturation
• The injecting pressure is lower than concrete strength, and don't damage building again.

2.1.4 Dual axes continual-pressure injector base AE151

Used in common concrete plane for cracks injecting.

2.1.5 Dual axes continual-pressure injector right-angle base AE152

Used in common concrete vertical angle for cracks injecting.

2.1.6 Dual axes continual-pressure injector rubber band AE153 for pressing

Used for dual axes continual-pressure injector AE150, it has a strength of 0.5kg/cm2／bar when it is pulled to 16cm that is the length between two hooks of injector when reagent was filled 30ml.

2.1.7 Super- particulate non-shrinking cement AC810

Used in common concrete when the width of cracks is more than 1.5mm.
It is difficult to go deep into thin-sand layer whose infiltration coefficient is lower than 5×10cm/s to common cement slurry, and can't go deep into cracks whose width is lower than 0.2mm too, because the diameter of common cement granule is between 40μm and 100μm.

The diameter of 50% super-particulate cement granule is between 4μm and 6μm, and the biggest is 30μm, and compare-surface area is 8000cm2/g. They are much smaller than common cement' diameter, so, super-particulate cement can be injected well into small cracks whose infiltration coefficient is 10-3~10-4cm/s.

2.1.8 general non-shrinking cement（pre-mixed）AC100

To be apt for repairing cracks of brick and porous structure.

2.2 Products series on high-pressure injecting method of A&GOOD AS2000

AS200, AS185, AS155, AS156, AS157, AS158

2.2.1 high-pressure injector AS200

Operate it with electric drill with high torsion and low rotate speed(750W,280∼650r.p.m), and have a injecting pressure of 6000psi.
So, it is propitious to inject resin into structure quickly, and the effect is different if injection is different.

2.2.2 High-pressure stop control injector pinhead AS185

Fix AS185 hardly in the hole after completed drilling, then, connect AS186 and high-pressure pipe AS200. Resin is control to can't backwash because of stop-backwash installation.

2.2.3 Resin of AS155, AS156, AS157 and AS158 for injecting

Table on applications of AS155,AS156,AS157 and AS158.

Table on performance of AS155, AS156, AS157 and AS158.

2.3 Products series on A&GOOD V-Cut repair method

AE111AB, AF806

2.3.1 Concrete adhesive -AE111AB referred at 2.1.1

2.3.2 Elastic resin for filling -AF806

AF806 is a single-liquid, no drooping and high-performance amic polymer. The sealant can be fixed well on the surface of basic material, especially on the flex cracks, when different primer is used according to different material.

3.0 Feasibility on Products series' application

Application performance
average★；good★★；very good★★★；excellent★★★★；nonuse－

4.0 Step on repair methods

4.1 AE150 continual pressure injecting method

	Carefully measure crack’ width, length and shape，confirm operation step and material used.
	Use steel wire brush or grinding wheel machine etc. to rubdown the surface that will be painted with sealant, and make stiff surface be exposed.
	Confirm injecting point, the distance between two cracks is about 25~30cm(almost as same as cracks’ depth)
	Install bases for injecting with sealant AE111, and the center of bases tallies with the center of cracks
	Seal the surface of cracks with sealant AE111 to protect resin from leaking(make a sealed belt that width is 30mm and thickness is 1~2mm)
	After sealant hardened, inject resin into cracks by AE150 continual pressure injecting method and injecting should be done from low point to high Point.
	Remove injectors after resin has hardened
	Knock down bases, and use grinding wheel machine to rubdown the surface and paint them with decorated material.

4.2 AS2000 high-pressure injecting method

The method includes high-pressure perfusion for structural cracks, high-pressure perfusion for work cracks, honeycomb perfusion (caused by bad disturbance) and perfusion for window waterproof on the outside wall.

4.2.1 high-pressure perfusion for work cracks

1. Drill structure with 5cm~10cm distance from the left or right of the lowest spot with 30~45 degree lean and 1/2 thickness of structure. Drilling from low spot to high spot, and hole distance of 20cm to 30cm is ok. To install injector AS185 when drilling is over.
2. To inject epoxy with high-pressure injector AS2000 from low spot to high spot after installed AS185. To inject other AS185 after find epoxy leaking from the surface of structure.
3. To wipe out AS185 after completed injecting, and fill the holes with AE111.
   

4.2.2 high-pressure perfusion for structure

1. Drill structure (hole diameter is 12mm) with 5cm~10cm distance from the left or right of the lowest crack with 30~45 degree lean and 1/2 thickness of structure. Drilling from low spot to high spot, and hole distance of 20cm to 30cm is ok. To install injector AS185 when drilling is over. In order to make injecting well, it must be noticed to make holes and cracks section cross, because cracks often are anomalous. To inject water into holes to judge if holes and cracks crossed, if use cement material or hydrophile material.
2. After installed AS185, inject material into holes with hi-pressure injector AS200 from low spot to high spot. Other AS185 will be injected after find injection to seep.
3. AS185 will be removed after injecting, then seal holes with AE111.
   

4.2.3 Honeycomb treatment

a. Drilling holes with 25cm~30cm distance around honeycomb and with 1/2 thickness of structure. Then, to install pinheads for injecting and inject material required with AS2000.
b. To inject from the lowest pinhead. After injection were filled and hardened and seeped, those higher pinheads should be injected. After injection and water reacted, all cracks will be filled and leakage will be treated well.
c. Remove pinheads and seal holes with sealant.

4.2.4 Leakage treatment for cracks of windows frame

a. To confirm that leakage spot is under window frame，according to standard windows, then install AS185 injector under the angles of window frame whose distance is 5cm~10cm to the concrete surface. Drilling should be leaned down.
b. To inject water before inject medicament, then inject medicament again and again until medicament seep.
c. Remove pinheads and seal holes with sealant.

4.3 V-Cut cracks repair method

4.3.1 Cut V-groove and fill it with epoxy AE111AB

1. Cut V or U groove beyond 0.5cm wide and 1cm thick. Clean out dust with hi-pressure air machine.
2. Fill groove with AE111AB
3. Next day, brush surface twice with elastic dope or cement paint
   

4.3.2 Cut V-groove and fill it with elastic glue AF806

1. Cut V or U groove beyond 0.5cm wide and 1cm thick.
2. Clean out dust with hi-pressure air machine and brush groove with primer
3. Fill groove with elastic glue
4. Next day, stick groove with glass fiber net (according to requirement)
5. Finally, brush surface twice with elastic dope or cement paint
   

5.0 Notice on use of crack repair methods

5.1 Crack action of general concrete members

5.1.1Anomalous cracks:

The width of cracks will reduce when the deepness of cracks increase.

5.1.2 Work cracks:

Often occur on the interface of new and old concrete, and the width of cracks will not obviously reduce when the deepness of cracks increase.

5.2 Material action

5.2.1 Mechanical performance of injection should be beyond that of structure. Tensile strength, bond strength and shear strength of members are very important, so, interface failure on the cracks isn't allowed when members are tested.

5.2.2 Low viscidity of injection and diameter of molecule is good. Thus, it can be confirmed that injection seeped through thin cracks.

5.2.3 Generally speaking, viscidity of injection will vary according to temperature and time varying. Viscidity of injection is the lowest when begin to react, then, viscidity is going up and occur early curdling. Viscidity of injection will increase with injecting time increase, so, pressing again and again will bring pressure what injecting required to attain good effect.

5.2.4 Injecting actionon anomalous cracks

The width of cracks will reduce when the deepness of cracks increase, so, continual pressure injecting method is very good.

6.0 Notice on crack repair construction

6.1 Epoxy resin and amic polymer series

6.1.1 The two products of impregnant aforesaid is flammable, so, it must be stored well. It is very important to prohibit fire and make fire protection.

6.1.2 Packing them on airproof, and storing them under shade. Solarization and storing under wateriness are prohibited. To use up quickly after unsealed.

6.1.3 To use them according to material statement, especially match appropriately to confirm good quality.

6.1.4 Mixture should be produced appropriately. If mill excessively, mixture will can't be used and have to make mixture again when occured early harden.

6.1.5 Keep ventilative at work room and operators must wear special clothing, cap, respirator, glove and glasses to protect themselves. Smoking and eating are prohibited on spot.

6.1.6 Recycled tools should be washed after they are used every time.

6.2 Cement series

6.2.1 They usually are apyrous, but they are cute to water. So, they can't be stored under wateriness.

6.2.2 To pack them on airproof and use up quickly after unsealed.

6.2.3 Tap water or distilled water should be used when to mix material. Water-cement ratio should be controlled according to specification, otherwise performance of material will be weak.

6.2.4 First, put 2/3 total water into pug pail; second, append powder; third, mix around them with low-speed mill machine; last, put water left into pail and mix around

6.2.5 Mixture should be produced appropriately. If mill excessively, mixture will can't be used and have to make mixture again when early harden occured.

6.2.6 Keep ventilative at work room and operators must wear special clothing, cap, respirator, glove and glasses to protect themselves.

6.2.7 Recycled tools should be washed after they are used every time.

7.0 Engineering quality control & check and accept

7.1 AE150 continual pressure injecting method

7.1.1 Clean up the spot and mark on the place for operation.

7.1.2 Burnish the surface plane.

7.1.3 Install AE150 whose distance is 25~30cm according to standard.

7.1.4 Install bases firmly.

7.1.5 Gaps between bases and cracks were sealed well.

7.1.6 Appropriate match of medicament.

7.1.7 Rightly to put medicament into injectors.

7.1.8 If injectors and bases were wrested tightly and if bases were off .

7.1.9 If to inject from low spot to high spot .

7.1.10 Observe if medicament was used up or leaked every ten minutes.

7.1.11 Install new injectors if medicament was used up until cracks were filled up and little medicament was left.

7.1.12 Keep aforesaid observation in 90 minutes.

7.1.13 Disassemble injectors and knock bases after 24 hours.

7.2 AS2000 high pressure injecting method

7.2.1 Clean up the spot and mark on the place for operation.

7.2.2 Install AE185 whose distance is 20~30cm according to standard.

7.2.3 Aperture, deepness and slope should be drilled appropriately according to design.

7.2.4 Install AS185 firmly in the holes drilled.

7.2.5 Appropriate match of medicament.

7.2.6 Press-meter of AS200 worked well.

7.2.7 Inject medicament from low spot to high spot, and inject other injector when medicament leaked from cracks.

7.2.8 If medicament leaked from AS185, to renew medicament in time.

7.2.9 Renew medicament after completed injecting if it is required.

7.2.10 Disassemble AS185 after 24 hours and sealed holes with AE111.

7.3 V-Cut cracks repair method

7.3.1 mark on the place for operation.

7.3.2 Cut V-grooves with sharp chisel or electric cutter.

7.3.3 V-grooves are cut with 5mm width and 1cm deepness, and increase width and deepness according to the ratio of 5mm width and 1cm deepness.

7.3.4 Clear V-groove with brush and dust collector.

7.3.5 Brush the surface of V-groove with special primer if use AF806 elastic resin.

7.3.6 Mix up AE111 with appropriate ratio.

7.3.7 Fill V-grooves from low spot to high spot and make them flat with reamer

7.3.8 Stick fiber net on the cracks if it was required according to design.

7.3.9 Brush elastic paint or general cement lacquer after 24 hours.

8.0 Engineering quality checking up

8.1 Before construction

8.1.1 Construction manufacturer should offer material specification and design certificate.

8.1.2 Material quantity should be assured by material manufacturer, and mustn't be Out Of Store.

8.1.3 Tools used should accord with safety and quality.

8.2 When construction

8.2.1 Material should be all carried to work spot one-off. Mnagement department must accept if material was carried to spot in batches.

8.2.2 Inform management department by written before material was carried to work spot.

8.2.3 Management department should sample material to test it according to spot.

8.3 After construction

8.3.1 To observe if cracks were filled up with eyes.

8.3.2 Confirm stop-water has been completed well if work spot leaked before.

8.3.3 Observe that honeycomb is repaired or not by knocking them with stick to listen.

8.3.4 Bore to sample with hollow drill, with 3cm diameter and 2 times diameter deepness (increase deepness according to the ratio of 3cm if need). Observe if medicament was filled up in the cracks.

8.3.5 Experimentalize to test performance of resist-press and resist-rip for checking up effect when use the method of AE150&AE160.