AUTHOR=Zhou Xiangming , Saini Harmeet , Kastiukas Gediminas 

TITLE=Engineering Properties of Treated Natural Hemp Fiber-Reinforced Concrete

JOURNAL=Frontiers in Built Environment

VOLUME=3

YEAR=2017

URL=https://www.frontiersin.org/journals/built-environment/articles/10.3389/fbuil.2017.00033

DOI=10.3389/fbuil.2017.00033

ISSN=2297-3362

ABSTRACT=<p>In recent years, the construction industry has seen a significant rise in the use of natural fibers, for producing building materials. Research has shown that treated hemp fiber-reinforced concrete (THFRC) can provide a low-cost building material for residential and low-rise buildings, while achieving sustainable construction and meeting future environmental targets. This study involved enhancing the mechanical properties of hemp fiber-reinforced concrete through the Ca(OH)<sub>2</sub> solution pretreatment of fibers. Both untreated (UHFRC) and treated (THFRC) hemp fiber-reinforced concrete were tested containing 15-mm length fiber, at a volume fraction of 1%. From the mechanical strength tests, it was observed that the 28-day tensile and compressive strength of THFRC was 16.9 and 10% higher, respectively, than UHFRC. Based on the critical stress intensity factor <inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo class="MathClass-open">(</mml:mo><mml:mrow><mml:msubsup><mml:mrow><mml:mi>K</mml:mi></mml:mrow><mml:mrow><mml:mtext>IC</mml:mtext></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msubsup></mml:mrow><mml:mo class="MathClass-close">)</mml:mo></mml:mrow></mml:math></inline-formula> and critical strain energy release rate <inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo class="MathClass-open">(</mml:mo><mml:mrow><mml:msubsup><mml:mrow><mml:mi>G</mml:mi></mml:mrow><mml:mrow><mml:mtext>IC</mml:mtext></mml:mrow><mml:mrow><mml:mtext>s</mml:mtext></mml:mrow></mml:msubsup></mml:mrow><mml:mo class="MathClass-close">)</mml:mo></mml:mrow></mml:math></inline-formula>, the fracture toughness of THFRC at 28 days was also found to be 7–13% higher than UHFRC. Additionally, based on the determined brittleness number (<italic>Q</italic>) and modulus of elasticity, the THFRC was found to be 11% less brittle and 10.8% more ductile. Furthermore, qualitative analysis supported many of the mechanical strength findings through favorable surface roughness observed on treated fibers and resistance to fiber pull-out.</p>