Use of Microcracking to Reduce Shrinkage Cracking in Cement-Treated Bases

Abstract

Shrinkage cracking occurs in cement-treated bases because of desiccation and cement hydration; eventually these cracks start to reflect through the pavement surfacing. Although initially considered cosmetic, these cracks open the pavement to water infiltration and increase the likelihood of accelerated pavement distress. Numerous options exist for minimizing the amount of reflective cracks that appear; microcracking is a promising approach. The microcracking concept can be defined as the application of several vibratory roller passes to the cement-treated base at a short curing stage, typically after 1 to 3 days, to create a fine network of cracks. In addition to the microcracked test sites, the contractor constructed moist-cured, dry-cured, and asphalt membrane–cured sites for comparison. Researchers used falling weight deflectometer (FWD) tests to control the microcracking process, periodic crack surveys to monitor crack performance, and FWD tests through time to track base moduli. Microcracking proved quite effective at reducing shrinkage cracking problems in the base; applying the procedure with three passes of the roller after 2 to 3 days of curing resulted in the best performance. In addition, researchers observed that, without microcracking, excessively high cement contents resulted in problematic cracking in the base even if they were cured according to good construction practice. Microcracking did not result in pavement damage or diminished inservice modulus; thus, microcracking should be considered a viable and inexpensive option to incorporate shrinkage crack control into the construction of cement-treated bases.

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References

Haas

R. C. G.

, and Topper

T. H.

. Thermal Fracture Phenomena in Bituminous Surfaces, In HRB Special Report 101: Control of Pavement Slipperiness and Asphalt Pavement Cracking, HRB, Washington, D.C., 1969, pp. 136–153.

Hajeck

J. J.

, and Haas

R. C. G.

. Predicting Low-Temperature Cracking Frequency of Asphalt Concrete Pavements. In Highway Research Record 407, HRB, Washington, D.C., 1972, pp. 39–54.

George

K. P.

Final Report on the Study of Criteria for Strength and Shrinkage Control of Cement-Treated Bases. University of Mississippi, University, 1968.

Bofinger

H. E.

, Hassan

H. O.

, and Williams

R. I. T.

. The Shrinkage of Fine-Grained Soil-Cement. TRRL Supplementary Report 398. Transport and Road Research Laboratory (TRRL), Crowthorne, England, 1978.

George

K. P.

Mechanism of Shrinkage Cracking of Soil-Cement Bases. In Highway Research Record 442, HRB, National Research Council, Washington, D.C., 1973, pp. 1–10.

Bofinger

H. E.

The Behaviour of Soil-Cement Pavements with Special Reference to the Problem of Cracking.

Proc., 4th Asian Regional Conference on Soil Mechanics and Foundation Engineering, Bangkok, Thailand, Vol. 4, 1971.

George

K. P.

Cracking in Pavements Influenced by Viscoelastic Properties of Soil-Cement. Presented at the 48th Annual Meeting of the Highway Research Board, Washington, D.C., 1969.

Scullion

, Sebesta

, Harris

J. P.

, and Syed

. A Balanced Approach to Selecting the Optimal Cement Content for Soil-Cement Bases. Report 404611-1. Texas Transportation Institute,

College Station, Tex.,

2000.

Nakayama

, and Handy

R. L.

. Factors Influencing Shrinkage of Soil-Cement. In Highway Research Record 86, HRB, National Research Council, Washington, D.C., 1965, pp. 15–27.

10.

Reflective Cracking in Cement Stabilized Pavements. Portland Cement Association, Skokie, Ill., 2003.

11.

Litzka

, and Haslehner

. Cold In-Place Recycling on Low-Volume Roads in Austria. Proc., 6th International Conference on Low Volume Roads, Minneapolis, Minn., 1995.

12.

Brandl

Mixed in Place Stabilisation of Pavement Structures with Cement and Additives.

Proc., 12th European Conference on Soil Mechanics and Geotechnical Engineering, Rotterdam, Netherlands, 1999.

13.

Scullion

Precracking of Soil-Cement Bases to Reduce Reflection Cracking: Field Investigation. In Transportation Research Record: Journal of the Transportation Research Board, No. 1787, Transportation Research Board of the National Academies, Washington, D.C., 2002, pp. 22–30.

14.

Scullion

, and Saarenketo

. Using Suction and Dielectric Measurements as Performance Indicators for Aggregate Base Materials. In Transportation Research Record 1577, TRB, National Research Council, Washington, D.C., 1997, pp. 37–44.

15.

Guthrie

W. S.

, Ellis

P. M.

, and Scullion

. Repeatability and Reliability of the Tube Suction Test. In Transportation Research Record: Journal of the Transportation Research Board, No. 1772, TRB, National Research Council, Washington, D.C., 2001, pp. 151–157.

16.

Syed

I. M.

Recent Developments in Characterizing Durability of Stabilized Materials. Presented at 82nd Annual Meeting of the Transportation Research Board, Washington, D.C., 2003.

17.

Guthrie

W. S.

, Young

T. B.

, Blankenagel

B. J.

, and Cooley

D. A.

. Early-Age Strength Assessment of Cement-Treated Base Material. In Transportation Research Record: Journal of the Transportation Research Board, No. 1936, Transportation Research Board of the National Academies, Washington, D.C., 2005, pp. 12–19.