Reliability assessment of carbon fiber mortar: Combined pulse velocity, point load, and compressive strength tests

Abstract

Cement mortar is used as an adhesive and plaster for brick walls, drainage channels or irrigation with river stones or mountain stones, and in the manufacturing of short revetments. The performance of cement mortar requires continuous improvement by construction materials researchers, scientists, and building contractors. Recently, carbon fiber sheet has gained popularity for use in retrofitting and improvement to the performance of building elements. This study aims to recycle small sheets of unused carbon fiber by cutting them into short carbon fiber (SCF) with a uniform length of 12 mm, which is used as an internal reinforcement in the cement mortar. All plain and fibrous mortar were prepared with a 50 mm cube mold. In addition, tests were conducted to provide reliable data regarding the application of recycled carbon fiber sheets as discrete fiber reinforcement in the improvement of cement mortar; these include ultrasonic pulse velocity (UPV), compressive strength, and point load strength index (PLSI) (known for performance rock testing in geotechnical and geological environments) tests. The test results for UPV, PLSI, and compressive strength showed that the addition of carbon fiber improves the performance of the mortar when compared to plain mortar. Furthermore, two simplified relationships are made: the first correlation was for PLSI with compressive strength, and the second correlation was for UPV with compressive strength. Finally, these correlations were compared with those of experimental tests obtained from published literature, thus demonstrating the correctness of the PLSI, compressive strength, and UPV values obtained in this study.

Keywords

• Pulse velocity
• Point load
• Compressive strength
• Carbon fiber
• Mortar