Open AccessComplex multifunctional additive for anchoring grout based on alkali-activated portland cement
Author(s) -
Wouter Schroeyers,
Oleh Petropavlovskyi,
Igor Rudenko,
Oleksandr Konstantynovskyi,
Artem V. Kovalchuk
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/907/1/012055
Subject(s) - materials science , portland cement , microstructure , crystallization , compressive strength , chemical engineering , composite material , cement , shrinkage , engineering
Complex multifunctional additive (further, CA) which consists of aluminum powder, surfactant, salt-electrolyte (NaNO 3 ) and calcium sulfate hemihydrate (CaSO 4 ·0.5H 2 O) is proposed for ensuring necessary properties of anchoring grouts based on alkali-activated portland cement (further, AAPC) presented by the system «ordinary portland cement clinker - sodium metasilicate». Specified consistency of fresh AAPC mortar along with it strength after hardening are provided by water reducing due to application of modified polyethylene glycol characterized by stability of molecular structure in AAPC hydration medium. CA influence on shrinkage mitigation in AAPC mortar is explained both water-reducing effect and gas release with volume increasing during formation of dispersive-coagulation structure. Expansion of crystallization-condensation structure is ensured due to stress of calcium hydrosulfoaluminate 3CaO·Al 2 O 3 ·3CaSO 4 ·32H 2 O and calcium hydronitroaluminate 3CaO·Al 2 O 3 ·Ca(NO 3 ) 2 ·10H 2 O which form due to presence of CaSO 4 ·0,5H 2 O and NaNO 3 in CA. Time matching of gas release with structure formation insures dense microstructure due to filling of pores by hydrated phases that causes lower excess stress during crystallization. CA ensures necessary performances of AAPC anchoring grout: consistency 190 mm; workability retention time 15 min; tensile strength in bending / compressive strength 6.1 / 25.7 MPa and 12.9 / 68.5 MPa in 1 d and 28 d agreeably; adhesion 0.9 MPa; linear extension up to +0.37 mm/m.