Distribution of Na⁺ and Mechanical Properties of Hardened Body of Alkali-activated Cementitious Materials

Abstract

To explore the distribution of and the mechanical properties (compressive strength) of the hardened body of alkali slag-fly ash cementitious materials, this study was conducted by using the XRD, FT-IR, SEM/EDS, and other test methods in three conditions: airtight drying (AD), airtight immersion (AI), and airtight soaking (AS). The 1D distribution law of free of hardened body under standard curing conditions was explored. The experimental results show that under standard curing conditions, the 1D distribution of within 0 d-3 d shows a ∨-shaped distribution, within 3–7 d show a ∧-shaped distribution, and within 7–28 d tends to be balanced. The test results of leaching rate show that the free was the most stable under AD conditions and the hardened body bound the most by XRD, FTIR and SEM/EDS. And the compressive strength of the hardened body was the highest. The compressive strength of 28th reached 95.9 MPa. The definite distribution of provides an important reference for the strength development and durability evaluation of the hardened body of alkali-excited cementitious materials.

Keywords

alkali-activated cementitious materials / ion migration / leaching rate / curing condition / compressive strength