Gather the following pavement design and construction details to assist in the investigation of early- age airfield pavement distresses. NOTE:This section is designed to be easily printed/copied and used on a project-by-project basis.
1. Design Details a. Project Specifics
i. Title:
ii. Location:
iii. Description:
b. Design concrete pavement thickness:
c. As-constructed concrete pavement thickness:
d. Typical Joint Spacing i. Transverse:
ii. Longitudinal:
e. Base type and thickness:
2. Concrete Mixture Information a. Cement type and source:
b. Cement grind history: fresh grind –or– not-fresh grind c. Cement content:
d. Supplementary Cementitious Materials (SCMs) i. Class C fly ash source:
ii. Class F fly ash source:
iii. Slag cement source:
e. SCM Content i. Class C fly ash:
ii. Class F fly ash:
iii. Slag cement:
f. Aggregate Data
i. Gradation: uniform –or– gap-graded –or– other ii. Gradation description:
iii. Coarse Aggregate 1. Type:
2. Source:
3. Amount:
iv. Fine Aggregate 1. Type:
2. Source:
3. Amount:
v. Coarse aggregate coefficient of thermal expansion:
g. Admixture Manufacturer, Type and Dosage i. Air-entraining:
ii. Water reducer:
iii. Other admixture:
3. Environmental Data
a. Weather condition for three (3) days prior to paving to 14 days after or present, whichever is earlier:
b. Hot/cold weather precautions taken:
c. Temperature readings for three (3) days prior to paving to 14 days after or present, whichever is earlier:
d. Rainfall history during and up to three (3) days after concrete paving or present, whichever is earlier:
Appendix F – Decision Tree for Early-Age Cracking
4. Construction Details a. Paving History
i. Start time:
ii. Finish time:
iii. Curing time:
b. Method used for minimizing bond for stabilized base:
c. Base surface condition:
d. Concrete Curing i. Curing method:
ii. Curing compound type and rate of application (if used):
iii. Number of days of moisture curing, if applicable:
e. Timing of Sawcut i. Transverse joints:
ii. Longitudinal joints:
f. Depth of Sawcut
i. Transverse joint – Specified: Actual range:
ii. Longitudinal joint – Specified: Actual range:
g. Dowel alignment verification results:
h. Early Age Loading History
i. Construction equipment loadings:
ii. Drill rig loading:
iii. Other:
5. Other Relevant Data
a. Develop distress maps, noting the ambient temperature at the time of distress survey. Es- timate or measure crack widths (contact ACPA about ordering a crack width comparator).
b. Update maps regularly (every day or every few days) to determine if the distress is pro- gressive and if cracks are getting wider.
Appendix F – Decision Tree for Early-Age Cracking
Table F.1. Decision Tree for Early-Age Cracking
Plastic Shrinkage Cracking
Random Cracking
Longitudinal Cracking
Transverse Cracking
Corner Cracking High rate of evapo-
ration from: warm temperature, low relative humidity, and/or high winds.
Slab to base bonding.
Late sawing for prevailing condi- tions.
Late sawing for prevailing condi- tions.
Early loading.
Dry concrete mix- ture.
Concrete slab friction against rough base or concrete penetra- tion into open graded base.
Shallow sawing of longitudinal con- traction joint in rela- tion to actualslab thickness.
Shallow sawing of longitudinal con- traction joint in rela- tion to actualslab thickness.
Excessive curling and warping due to temperature changes or mois- ture loss.
Dry aggregates. Reflection crack- ing (from base cracking).
Slabs too wide in relation to thick- ness and length.
Slabs too long in relation to thick- ness & width.
Dowel bars too close to each other at trans- verse and longi- tudinal joints.
Late or inadequate curing.
Late or inade- quate curing.
Temperature drop due to sudden cold front or rain.
Temperature drop due to sudden cold front or rain.
Late or inade- quate curing.
Delay in finishing. Late sawing for prevailing condi- tions.
Misaligned or bonded dowels in adjacent longitudi- nal joints prevent- ing cracked joints from functioning properly.
Misaligned or bonded dowels in adjacent transverse joints preventing cracked joints from functioning prop- erly.
Misaligned or bonded dowels in adjacent trans- verse joints pre- venting cracked joints from func- tioning properly.
Temperature drop due to sudden cold front or rain.
Shallow sawing of contraction joints in relation to ac- tualslab thick- ness.
Excessive curling or warping.
Excessive curling or warping.
Material incompati- bility leading to higher concrete shrinkage & delay in setting time.
Poor aggregate gradation (sand too fine; gap gra- dation).
Poor aggregate gradation (sand too fine; gap grada- tion).
Retarded concrete.
Poor aggregate gradation (sand too fine; gap gradation).
Early loading. Poor aggregate gradation (sand too fine; gap gradation).
Infill lane restraints. High shrinkage concrete.
Late or inadequate curing.
Early loading.
Possible CausesCracking Type
Table F.1. Decision Tree for Early-Age Cracking (continued)
Cracking Just Ahead of Sawing
Late Cracking
Sympathy Cracking
Settlement Cracking over Steel
Re-entrant Cracking Late sawing for pre-
vailing conditions.
Early age slab bottom cracking fi- nally becoming visible.
Joints in paved lane do not match joints in adjacent lanes.
Higher slump con- crete.
Use of odd- shaped slab panels.
Sawing against high wind.
Frost heave. Different joint cracking patterns in adjacent lanes.
Shallow dowel bars or tiebars.
Rigid penetra- tions (in-place structures).
Foundation settle- ment.
Joints match in lo- cation but not in type.
Delay in setting time.
Possible CausesCracking Type
Table F.2 Investigative Technique for Early-Age Cracking
Plastic Shrinkage
Cracking
Random Cracking
Longitudinal Cracking
Transverse Cracking
Corner Cracking
Settlement Cracking over Steel Check quality of
curing compound
Obtain cores through base to check slab to base bond.
Obtain core to check depth of cracking and ag- gregate break- age.
Obtain core to check depth of cracking and aggregate breakage.
Obtain core to check depth of cracking and aggregate breakage.
Check dowel depths using a covermeter, GPR , or mag- netic imagin- ing, or by coring.
Check quality of curing com- pound.
Check quality of curing compound.
Check qual- ity of curing compound.
Check quality of curing compound.
Investigative TechniquesCracking Type