Title: Shrinkage Cracking and Durability Characteristics of Cellulose Fiber Reinforced Concrete

Author(s): M. Sargaphuti, S. P. Shah, and K. D. Vinson

Publication: Materials Journal

Volume: 90

Issue: 4

Appears on pages(s): 309-318

Keywords: cracking (fracturing); durability; fiber reinforced concrete; reinforcing; shrinkage; temperature; tests; Materials Research

DOI: 10.14359/3879

Date: 7/1/1993

Abstract:
Shrinkage cracking is a major concern for concrete, especially for flat structures such as highway pavement slabs for parking garages and walls. One of the methods to reduce the adverse effects of shrinkage cracking is to reinforce concrete with short, randomly distributed fibers. The efficiency of cellulose fiber in arresting cracks in cementitious composites was studied. A ring-type specimen was developed for a restrained shrinkage cracking test. Concretes reinforced with six different types of cellulose fibers, with a fiber content of 0.5 percent by volume (approximately 1 percent by weight of cement) were tested. Cellulose fiber reinforcement showed an ability to reduce the crack width significantly (as compared to unreinforced concrete). For comparison, concrete reinforced with 0.5 percent cellulose fibers showed excellent performance equal to 0.5 polypropylene fibers (maximum crack width about 1/3 that of plain concrete). The long-term mechanical performance of cellulose and polypropylene fiber reinforced concrete was also evaluated. Two types of accelerated aging were used: hot-water soak and repeated wet/dry cycling, respectively. The toughness of unaged cellulose and polypropylene fiber reinforced concrete was approximately 40 and 90 percent higher, respectively, than that of plain concrete specimens. After 60 days of hot water treatment, the toughness performance of the composite was unchanged. However, after being subjected to repeated wet/dry cycling, a 40 percent drop in toughness of both cellulose and polypropylene fiber composite was observed. The influence of the cellulose fiber reinforcement (0.5 percent addition) on other concrete properties, such as free shrinkage, compressive strength, flexural strength, and Young's modulus, were also investigated.