CONCRETE REPAIR IN ACTION: USING THE MANUAL AS A GUIDE. Christen Longoria, P.E. San Antonio District Project Engineer

Transcription

1 CONCRETE REPAIR IN ACTION: USING THE MANUAL AS A GUIDE Christen Longoria, P.E. San Antonio District Project Engineer

2 TxDOT CONCRETE REPAIR MANUAL Step-by-Step repair procedures for use on new and existing concrete Ch. 1 Introduction Ch. 2 Damage Assessment and Repair Types Ch. 3 Repair Materials and Procedures Each section is a stand-alone document 2

3 Defining Spalls Minor Spall Less than 1 in deep Less than 12 sq in 3

4 Defining Spalls Intermediate Spall Exposes outer reinforcing steel Max depth 6 in 4

5 Defining Spalls Major Spall Extends beyond outer cage Significant stresses 5

6 Minor Spalls - Materials Neat Epoxy or Epoxy Mortar DMS 6100 Epoxies and Adhesives 6

7 Minor Spalls - Materials Neat Epoxy or Epoxy Mortar MPL for Epoxies and Adhesives Type VIII Epoxy Mortar 7

8 Minor Spalls Repair Procedure Surface Preparation Remove damaged/loose concrete Avoid damage to reinforcement Hand tools or 15 lb hammer Clean and sound Do NOT remove reinforcing steel Mixing Manufacturers Instructions Low speed drill and mixing paddle Slowly add sand or aggregate Time 8

9 Minor Spalls Repair Procedure Epoxies Epoxy Mortar Application Bonding layer Trowel application Limit depth to 1 inch Neat Epoxy Application Clean and dry Brush, Roll or Scrub Total coverage 9

10 Intermediate Spalls Materials Materials Proprietary, bagged Concrete Compressive strengths Slower strength development DMS 4655 MPL for Concrete Repair Materials Type A-3 (Vertical, overhead, less than 3 in) Type A-4 (Vertical, overhead, up to 6 in deep) Limit thickness 10

11 Intermediate Spalls Repair Procedure Surface Preparation Reinforcement Perimeter Remove damaged or loose concrete Avoid damage to reinforcement Hand Tools or 15 lb hammer Clean and Sound Clearance Pre-stressing strands Remove rust Saw cut patch Hand-held grinders or saws Roughen substrate 11

12 Intermediate Spalls Repair Procedure Epoxy Anchors Drill and clean anchor holes Proper embedment Cover Blast clean Dowels Hole size and depth Brush clean Air compressor Epoxy 1/3 full Insert dowel 12

13 Intermediate Spalls Repair Procedure 13

14 Intermediate Spalls Repair Procedure 14

15 Intermediate Spalls Repair Procedure Mixing Follow manufacturer s instructions Mixing less than 1 CY Low speed drill Mixing more than 1 CY Mortar mixer Short working times Don t overmix Application Temperature Ranges Saturated Surface-Dry (SSD) Substrate Trowel application Form and pour application 15

16 Intermediate Spalls Repair Procedure Curing Moist curing Forms in place 72 hr min Finishing Aesthetics Blending 16

17 Major Spall Repair Batched concrete Same mix as design mix Follow concrete specifications 17

18 Major Spall Repair Method Surface Prep Mixing Anchors or Dowels Forming Curing 18

19 Major Spall Repair Batched concrete Match parent concrete TxDOT specifications 19

20 Major Spall Repair Batched concrete Fails at bond line 20

21 Bridge Deck Spall Repair Defined by Depth Partial Bridge Deck Repairs 21

22 Bridge Deck Spall Repair Defined by Depth Deck Repairs over Precast Panels 22

23 Bridge Deck Spall Repair Defined by Depth Full Depth Repairs 23

24 Bridge Deck Spall Repair Defined by Speed Immediate need to return to service 4 hours (Type B) 8 hours (Type A) 24 hours (Class K) 2 to 4 Days (Class S) 24

25 Bridge Deck Spall Repair Concrete Removal Tools Uniform depth No damage to surrounding concrete or steel 25

26 Bridge Deck Spall Repair Surface Preparation Blast clean SSD condition Reinforcing Steel Plans/Engineer Bend and secure 26

27 Bridge Deck Spall Repair Placement 27

28 Bridge Deck Spall Repair Finishing Curing 28

29 Bridge Deck Spall Repair Improper Method Maintenance issues 29

30 Other Repair Methods Crack repairs Pressure Injected Epoxy Gravity Fed Epoxy Surface Sealing Voids due to Honeycombing Damage over traffic Piling repairs Post fabrication and during driving Taking, Marking, and Patching Cores Trimming or cutting pre-stressed concrete girder ends 30

31 THANK YOU! Special Thanks: Bonnie Longley, P.E. San Antonio Bridge Engineer James Meuth and the S.A. Bridge Crew For questions please contact: 31