Synthesis of a one-part geopolymer system for soil stabilizer using fly ash and volcanic ash

Section 3.2 (Unconfined compressive strength; page not provided) reports a maximum strength of 971 kPa, or 0.971 MPa—above the claimed 0.8 MPa threshold. Other tested formulations were below 0.8 MPa, but the paper does not say that all its strength values fail that threshold; it instead discusses a 75 kPa requirement from the National Structural Code of the Philippines, not ASTM D 4609. (LLM, conf=0.87)

Checked by a reasoning model — may be wrong.

The Introduction describes fly ash as naturally pozzolanic, and §3.2 reports that increasing its proportion in an alkali-activated geopolymer mixture increased the compressive strength of stabilized soil. The paper does not establish the claim’s specific mechanism that fly ash binds to minerals in soil; the tested stabilizer also contained volcanic ash and alkali activators. Page numbers are not available for these passages. (LLM, conf=0.86)

Section 3.3, Sulfuric acid resistance (page not provided), reports higher strength after 28 days of acid immersion and suggests that the additional time may have allowed further curing. It does not establish that longer curing is required to reach an optimum strength; the proposed effect of curing time is hedged. (LLM, conf=0.86)

Section 3.2 (Unconfined compressive strength) reports that increasing fly ash increased the compressive strength of geopolymer-stabilized soil. The paper does not report a reduction in soil swelling or shrinkage; its soil characterization in Section 3.1.1 describes the soil as non-plastic silty sand. (LLM, conf=0.88)

The Introduction describes silica- and alumina-rich fly ash as a precursor for soil stabilization and explains that aluminosilicate feedstock dissolves in the presence of an alkali activator. However, §3.1.2 identifies this study’s fly ash as Class F, not Class C, and the paper uses volcanic ash rather than GGBFS. This source therefore does not support the claim’s specific pairing of Class C fly ash and GGBFS. (LLM, conf=0.88)

Section 3.2 (page not available) says a low proportion of sodium hydroxide in the alkali activator could yield low-strength stabilized soil. It does not test NaOH solution molarity or report that excessively high molarity lowers strength; within the ratios studied, it says strength tends to increase as the amount of sodium hydroxide increases. The Introduction describes this study as using solid activators rather than an activator solution. (LLM, conf=0.88)

Section 3.2 discusses how alkali-activator composition affects strength, and section 3.5 describes a homogeneous structure in a soaked specimen. Neither passage links a rising solid-to-liquid ratio to reduced homogeneity or to insufficient activator. Searches for that ratio and the proposed explanation found no supporting passage in our copy; page numbers were not provided. (LLM, conf=0.72)