This paper summarizes the findings of two surveys conducted to understand existing techniques utilized for crack sealing in United States. For the first survey, personnel from 21 TxDOT districts were contacted and their opinions on the crack sealing techniques and materials were gathered. The level of satisfaction in terms of performance, safety, ease of use, and cost were evaluated through the district correspondence.
In the second survey, information was gathered from other states on the crack and joint sealing material and techniques. 9 states returned the survey forms. Information on different states’ experience on hot and cold pour sealant techniques, safety, ease of installation, performance, and the associated costs were collected. For these two surveys, the same questionnaire was used.
Survey of TxDOT Districts
Responses from 21 of the 25 TxDOT districts indicates that hot poured crack sealant is still the common material used in most of the TxDOT districts. All the districts have used hot pour sealants. Atlanta, Austin, Childress, El Paso, Lubbock, Odessa, Paris, Pharr, Tyler, Wichita Falls and Yoakum have also used cold pour sealants.
Among the districts, all of them used the compressed air method for crack cleaning. Only the districts of Dallas, Houston and Paris used routing. No districts used sawing, wire brush or hot compressed air lance. Hot pour cost varied between $ 0.10 and $ 0.36 per foot, whereas cold pour cost between $ 0.13 and $ 0.20 per foot. The type of cracks that were sealed also varied. All districts reported sealing transverse cracks. With an exception of Lubbock, districts reported sealing of longitudinal cracks. Sealing of reflection and edge cracks are also reported by 18 districts. 12 districts stated that they seal fatigue cracks. The width of the cracks sealed was typically under _ inch. Some reported to seal wider cracks, but cracks wider than 1 inch were rarely reported to be sealed. When sealing the cracks, the majority of the districts used rubber squeegee for hot and cold pour sealants. The sealing shoe was used only by four districts, whereas the metal squeegee was used by only three districts.
The participating districts rated performance of the hot pour and cold pour sealants for 10 different questions. Ratings used were "poor", "fair", "good" and "excellent". Tables 1 through 10 summarize the ratings in terms of the percentage of the survey results.
Table 1. Percentage of Survey Results for Resistance to Being Forced Out by Traffic for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
0 |
25 |
42 |
33 |
|
Hot Pour |
0 |
11 |
63 |
26 |
Table 2.2. Percentage of Survey Results for Resistance to Oxidation for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
0 |
19 |
45 |
36 |
|
Hot Pour |
0 |
11 |
50 |
39 |
Table 2.3. Percentage of Survey Results for Resistance to Becoming Brittle for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
0 |
0 |
58 |
42 |
|
Hot Pour |
0 |
11 |
56 |
33 |
Table 2.4. Percentage of Survey Results for Resistance to Particles Entering Cracks for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
0 |
27 |
55 |
18 |
|
Hot Pour |
0 |
22 |
56 |
22 |
Table 2.5. Percentage of Survey Results for Resistance to Flushing or Bleeding for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
0 |
8 |
42 |
50 |
|
Hot Pour |
39 |
39 |
11 |
11 |
Table 2.6. Percentage of Survey Results for Ability to Bond to Pavement for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
0 |
17 |
50 |
33 |
|
Hot Pour |
0 |
0 |
53 |
47 |
Table 2.7. Percentage of Survey Results for Abrasion Resistance for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
0 |
10 |
60 |
30 |
|
Hot Pour |
0 |
14 |
64 |
22 |
Table 2.8. Percentage of Survey Results for Ability to Rebond for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
9 |
27 |
46 |
18 |
|
Hot Pour |
17 |
5 |
67 |
11 |
Table 2.9. Percentage of Survey Results for Effectiveness of Sealing for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
0 |
8 |
59 |
33 |
|
Hot Pour |
0 |
0 |
47 |
53 |
Table 2.10. Percentage of Survey Results for the Period the Sealant is Effective for Cold and Hot Pour Sealants
|
1 Year |
2 Years |
3 Years |
4 Years |
5 Years |
|
|
Cold Pour |
25 |
25 |
25 |
12 |
12 |
|
Hot Pour |
0 |
7 |
40 |
33 |
20 |
Hot pour sealants were ranked poor or fair for resistance to flushing or bleeding by the majority of the districts as can be seen in Table 2.5. In overall evaluation of the survey, hot pour performed better than the cold pour sealants.
Among the 9 states, only New Jersey used wire brush. All the other states used compressed air. New York, Oregon and Pennsylvania also used routing. Sawing was used as a method by the states of North Carolina and Oregon. Hot compressed air was used by Alaska, North Carolina, Oregon and Pennsylvania. The type of sealants used also varied among different states. All the states used hot pour sealants. Alaska, New Jersey, Maryland, North Carolina and Oregon also used cold pour sealants. Hot pour cost varied between $ 0.13 and $ 1.7 per foot, whereas cold pour cost varied between $ 0.17 and $ 0.3 per foot. All states reported to seal transverse, longitudinal and reflection cracks. Most of the states reported sealing of edge cracks. Some of the participating states stated that they seal fatigue and block cracks. The width of the cracks sealed was typically between _ and 1 inch. Six of them reported to seal cracks under _ inch, however cracks wider than 1 inch were not reported to be sealed. When sealing the cracks, the majority of the states used a rubber squeegee for hot and cold pour sealants. The sealing shoe was also commonly used by nearly half of the participating states, whereas usage of the metal squeegee was not reported. Detailed documentation of the survey conducted on different states is included in Appendix B.
Performance of the hot pour and cold pour sealants were rated by the participating states for 10 different questions. Ratings used were "poor", "fair", "good" and "excellent". Tables 2.11 through 2.20 summarize the ratings in terms of the percentage of the survey results. Appendix B gives more detailed data on this part of the survey.
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
33 |
67 |
0 |
0 |
|
Hot Pour |
0 |
22 |
33 |
45 |
Table 2.12. Percentage of Survey Results for Resistance to Oxidation for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
33 |
0 |
67 |
0 |
|
Hot Pour |
0 |
45 |
22 |
33 |
Table 2.13. Percentage of Survey Results for Resistance to Becoming Brittle for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
67 |
0 |
33 |
0 |
|
Hot Pour |
0 |
22 |
45 |
33 |
Table 2.14. Percentage of Survey Results for Resistance to Particles Entering Cracks for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
0 |
67 |
33 |
0 |
|
Hot Pour |
0 |
0 |
56 |
44 |
Table 2.15. Percentage of Survey Results for Resistance to Flushing or Bleeding for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
0 |
100 |
0 |
0 |
|
Hot Pour |
11 |
11 |
67 |
11 |
Table 2.16. Percentage of Survey Results for Ability to Bond to Pavement for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
33 |
67 |
0 |
0 |
|
Hot Pour |
0 |
22 |
22 |
56 |
Table 2.17. Percentage of Survey Results for Abrasion Resistance for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
33 |
33 |
33 |
0 |
|
Hot Pour |
0 |
45 |
33 |
22 |
Table 2.18. Percentage of Survey Results for Ability to Rebond for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
33 |
33 |
33 |
0 |
|
Hot Pour |
0 |
57 |
43 |
0 |
Table 2.19. Percentage of Survey Results for Effectiveness of Sealing for Cold and Hot Pour Sealants
|
Poor |
Fair |
Good |
Excellent |
|
|
Cold Pour |
25 |
75 |
0 |
0 |
|
Hot Pour |
0 |
11 |
44 |
44 |
Table 2.20. Percentage of Survey Results for the Period the Sealant is Effective for Cold and Hot Pour Sealants
|
1 Year |
2 Years |
3 Years |
4 Years |
5 Years |
|
|
Cold Pour |
20 |
40 |
40 |
0 |
0 |
|
Hot Pour |
0 |
12 |
25 |
25 |
38 |
For 7 out of 9 questions, cold pour sealants were ranked poor by some of the participating states. Hot pour sealants were ranked poor only for resistance to flushing or bleeding by the some of the states as can be seen in Table 2.15. In overall evaluation of the survey, hot pour performed evidently better than the cold pour sealants.