Strength, Chloride Ion Penetration, and Nanoscale Characteristics of Concrete Prepared with Nano-Silica Slurry Pre-Coated Recycled Aggregate

It has become a feasible green building development strategy to prepare recycled aggregate concrete (RAC) by processing construction and demolition (C&D) wastes into coarse (RCA). On the other hand, defects such as low strength easy cracking of RAC seriously limit its application in materials. In this paper, RCA was strengthened pre-coated nano-silica (NS) slurry improve performance. The effect nano-modified (MRCA) on compressive chloride ion penetration after replacing ordinary or natural (NCA) studied. SEM, MIP nano-indentation techniques were used evaluate MRCA concrete. results show that replacement NCA with reduces mechanical property Under same conditions, (MRAC) are better than those RAC. Compared RAC, width interface transition zone (ITZ) indentation modulus MRAC increased 23.1% 89.4%. This is mainly attributed filling NS slurry, which number pores microfractures surface RCA, pozzolanic consumes part calcium hydroxide produce more silicate hydrate gel, improves ITZ addition, use pre-coating modified good economic environmental benefits.