Use of Fiber-Reinforced Cements in Masonry Construction and Structural Rehabilitation

TLDR

Fiber reinforcement has been well studied in concrete, but its application to masonry and structural rehabilitation remains underexplored and requires further research. This paper reviews a decade of the author’s work on fiber‑reinforced cements for masonry and rehabilitation projects. A 0.5 % micro‑fiber mix in type N Portland cement lime mortar works for most masonry joints; clay units benefit from high‑water FRM while concrete units prefer drier mixes (targeting 130 % and 110 % flow), earth‑block masonry shows improved damage and water‑pressure resistance, and the proposed FRC retrofit for reinforced concrete slabs markedly increases capacity at lower cost than conventional fiber‑reinforced polymers.

Abstract

The use of fiber reinforcement in traditional concrete mixes has been extensively studied and has been slowly finding its regular use in practice. In contrast, opportunities for the use of fibers in masonry applications and structural rehabilitation projects (masonry and concrete structures) have not been as deeply investigated, where the base matrix may be a weaker cementitious mixture. This paper will summarize the findings of the author’s research over the past 10 years in these particular applications of fiber reinforced cements (FRC). For masonry, considering both mortar and mortar-unit bond characteristics, a 0.5% volume fraction of micro fibers in type N Portland cement lime mortar appear to be a viable recipe for most masonry joint applications both for clay and concrete units. In general, clay units perform better with high water content fiber reinforced mortar (FRM) while concrete masonry units (CMUs) perform better with drier mixtures, so 130% and 110% flow rates should be targeted, respectively. For earth block masonry applications, fibers’ benefits are observed in improving local damage and water pressure resistance. The FRC retrofit technique proposed for the rehabilitation of reinforced concrete two-way slabs has exceeded expectations in terms of capacity increase for a relatively low cost in comparison to the common but expensive fiber reinforced polymer applications. For all of these applications of fiber-reinforced cements, further research with larger data pools would lead to further optimization of fiber type, size, and amount.