Title:
Synthetic Fibers and Rheology Modifier: Effects on Settlement Cracking
Author(s):
Osama Al-Qassag, Ryan Brettmann, David Darwin, Matthew O’Reilly, and Rouzbeh Khajehdehi
Publication:
Materials Journal
Volume:
119
Issue:
1
Appears on pages(s):
289-296
Keywords:
crack-reducing technologies; fibers; low cover; rheologymodifying admixture; settlement cracking; slump; testing; viscositymodifying admixture (VMA)
DOI:
10.14359/51734302
Date:
1/1/2022
Abstract:
A test procedure was developed to evaluate the effect of different techniques to limit settlement cracking over reinforcing steel with low concrete cover. Various specimen configurations and methods of finishing and curing were investigated. It was found that a clear cover of 1-1/8 in. (29 mm) over a No. 6 (No. 19) bar and covering the specimens after placement with sloped hard plastic enclosed in plastic sheeting provided a suitable method for obtaining clearly visible settlement cracks for concrete with slumps ranging from under 2 in. (50 mm) to over 8 in. (205 mm). The test specimen was then used to evaluate the effectiveness of a rheology-modifying admixture and four types of synthetic fibers on settlement cracking. Eighty-eight concrete batches were tested for mixtures with a cement paste (cement and water) content of 27 percent by volume and a water-cement ratio (w/c) of 0.45. The results show that the addition of the rheology-modifying admixture or fibers greatly reduces settlement cracking over reinforcing steel with low concrete cover.
Related References:
Al-Qassag, O.; Darwin, D.; and O’Reilly, M., 2015, “Effect of Synthetic Fibers and a Rheology Modifier on Settlement Cracking of Concrete,” SM Report No. 116, University of Kansas Center for Research, Inc., Lawrence, KS, Dec., 113 pp.
ASTM C1064/C1064M-12, 2012, “Standard Test Method for Temperature of Freshly Mixed Hydraulic-Cement Concrete,” ASTM International, West Conshocken, PA, 3 pp.
ASTM C143/C143M-15, 2015, “Standard Test Method for Slump of Hydraulic-Cement Concrete,” ASTM International, West Conshocken, PA, 4 pp.
ASTM C150/C150M-15, 2015, “Standard Specification for Portland Cement,” ASTM International, West Conshocken, PA, 9 pp.
ASTM C173/C173M-14, 2014, “Standard Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method,” ASTM International, West Conshocken, PA, 9 pp.
Babaei, K., and Purvis, R. L., 1995, “Prevention of Cracks in Concrete Bridge Decks: Report on Surveys of Existing Bridges,” Report PA-FHWA-95-001+89-01, 100 pp.
Brettmann, R.; Darwin, D.; and O’Reilly, M., 2015, “Developing a Test Procedure to Evaluate Settlement Cracking Performance,” SL Report 15-2, University of Kansas Center for Research, Inc., Lawrence, KS, 40 pp.
Dakhil, F. H.; Cady, P. D.; and Carrier, R. E., 1975, “Cracking of Fresh Concrete as Related to Reinforcement,” ACI Journal Proceedings, V. 72, No. 8, Aug., pp. 421-428.
Darwin, D.; Browning, J.; and Lindquist, W., 2004, “Control of Cracking in Bridge Decks: Observations from the Field,” Cement, Concrete and Aggregates, V. 26, No. 2, Dec., pp. 148-154. doi: 10.1520/CCA12320
Darwin, D.; Browning, J.; Lindquist, W.; McLeod, H. A. K.; Yuan, J.; Toledo, M.; and Reynolds, D., 2010, “Low-Cracking, High-Performance Concrete Bridge Decks – Case Studies Over the First 6 Years,” Transportation Research Record: Journal of the Transportation Research Board, V. 2202, No. 1, pp. 61-69. doi: 10.3141/2202-08
Draper, N. R., and Smith, H., 1981, Applied Regression Analysis, second edition, John Wiley & Sons, Inc., New York, 709 pp.
Feng, M., and Darwin, D., 2020, “Implementation of Crack-Reducing Technologies for Concrete in Bridge Decks: Synthetic Fibers, Internal Curing, and Shrinkage-Reducing Admixtures,” SM Report No. 136, University of Kansas Center for Research, Inc., Lawrence, KS, 242 pp.
Khajehdehi, R., and Darwin, D., 2018, “Controlling Cracks in Bridge Decks,” SM Report No. 129, University of Kansas Center for Research, Inc., Lawrence, KS, 218 pp.
Khajehdehi, R.; Darwin, D.; and Feng, M., 2021, “Dominant Role of Cement Paste Content on Bridge Deck Cracking,” Journal of Bridge Engineering, ASCE, V. 26, No. 7, p. 04021037. doi: 10.1061/(ASCE)BE.1943-5592.0001738
Krauss, P. D., and Rogalla, E. A., 1996, “Transverse Cracking in Newly Constructed Bridge Decks,” National Cooperative Highway Research Program Report 380, Transportation Research Board, Washington, DC, 126 pp.
Lindquist, W. D.; Darwin, D.; and Browning, J. P., 2005, “Cracking and Chloride Contents in Reinforced Concrete Bridge Decks,” SM Report No. 78, University of Kansas Center for Research, Inc., Lawrence, KS, 452 pp.
Lindquist, W.; Darwin, D.; Browning, J.; McLeod, H. A. K.; Yuan, J.; and Reynolds, D., 2015, “Implementation of Concrete Aggregate Optimization,” Construction and Building Materials, V. 74, Jan., pp. 49-56. doi: 10.1016/j.conbuildmat.2014.10.027
Lindquist, W. D.; Darwin, D.; Browning, J.; and Miller, G. G., 2006, “Effect of Cracking on Chloride Content in Concrete Bridge Decks,” ACI Materials Journal, V. 103, No. 6, Nov.-Dec., pp. 467-473.
McLeod, H. A. K.; Darwin, D.; and Browning, J., 2009, “Development and Construction of Low-Cracking High-Performance Concrete (LC-HPC) Bridge Decks: Construction Methods, Specifications, and Resistance to Chloride Ion Penetration,” SM Report No. 94, University of Kansas Center for Research, Inc., Lawrence, KS, 815 pp.
Ritchie, A. G. B., and Rahman, T. A., 1974, “The Effect of Fiber Reinforcements on the Rheological Properties of Concrete Mixes,” Fiber Reinforced Concrete, SP-44, American Concrete Institute, Farmington Hills, MI, pp. 29-44.
Rogalla, E. A.; Krauss, P. D.; and McDonald, D. B., 1995, “Reducing Transverse Cracking in New Concrete Bridge Decks,” Concrete Construction, V. 40, No. 9, pp. 735-738.
Schmitt, T. R., and Darwin, D., 1995, “Cracking in Concrete Bridge Decks,” SM Report No. 39, University of Kansas Center for Research, Inc., Lawrence, KS, Apr., 151 pp.
Schmitt, T. R., and Darwin, D., 1999, “Effect of Material Properties on Cracking in Bridge Decks,” Journal of Bridge Engineering, ASCE, V. 4, No. 1, Feb., pp. 8-13. doi: 10.1061/(ASCE)1084-0702(1999)4:1(8)
Suprenant, B. A., and Malisch, W. R., 1999, “The Fiber Factor – Lab Tests Show the Benefits of Using Synthetic Fibers to Limit Subsidence Cracking of Reinforced Concrete,” Concrete Construction, Oct., 4 pp.