Durability of a novel effective microfine cementitious grouting material in corrosion environments

Abstract

High durability requirements of grouting materials have been proposed gradually in corrosion environments. To evaluate and improve durability of grouting material, ordinary Portland cement (OPC), microfine Portland cement (MC), microfine sulphoaluminate cement (MSAC), and newly developed effective microfine cement-based grout (EMCG) were selected. Early impermeability, flexural strength (FS), unconfined compressive strength (UCS), corrosion resistance coefficient (KFS and KUCS), volumetric and mass variations, characteristics of fracture surface, corrosion mineral, microstructure and pore size distribution are studied synergistically. The water-binder ratios (W/Bs) of OPC and microfine grouts are 1.0 and 1.0–1.5. The concentrations of sodium sulfate and sodium chloride corrosion solutions are 0.3%, 5% and 10%. Corrosion ages are 3d, 7d, 28d, 91d, 181d and 360d. The 3d or 7d impermeable pressure of EMCG exceeds 1.0 MPa. The anti-corrosion strength and durability of EMCG under the W/B of 1.5 are acceptable. KFS and KUCS of MC and OPC are low. Although KFS and KUCS of MSAC are over 1.0, its strength needs to be enhanced further. The KFS, KUCS and actual strength of EMCG are satisfied. The corrosion expansion rate of EMCG is the lowest (no more than 0.058%), and its effectiveness of hydration and anti-corrosion is the optimal. The EMCG’s interconnection degrees among gels are the highest, its number of holes is the minimum and its pore structure is satisfactory. The EMCG satisfies demands of high durability in corrosion environments in underground, hydraulic, civil and ocean engineering.