Porosity/(SiO₂ and Al₂O₃ Particles) Ratio Controlling Compressive Strength of Zeolite-Cemented Sands

Abstract

The practice of soil treatment using cement and zeolite is an approach that can be widely used in soil stabilization particularly in road construction, as a support layer for shallow foundations, to strengthen slopes, and to prevent sand liquefaction. The present research intends to quantify the impact of both amounts of cement and zeolite, porosity index, porosity/cement and porosity/SiO₂ and Al₂O₃ particles ratio on zeolite cemented sand mixtures by the assessment of unconfined compressive strength (UCS). A program of unconfined compression tests considering three distinct porosity ratio, four cement contents (2, 4, 6 and 8%) and six different percent of cement replacement by zeolite (0, 10, 30, 50, 70 and 90%) is performed in this study. Results indicate that cement replaced by zeolite at optimum proportion of 30%, the value of improved UCS of the cement sand specimens due to zeolite and cement chemical properties are exploited. Increasing cement content and porosity of the compacted mixture, the efficiency of using zeolite rises. In this paper, it has been shown that for the zeolite–cement–sand mixtures, UCS increases via cement content (C) raise and porosity (η) reduction and a power function is well-adapted to fit both UCS-C and UCS-η. Finally, key parameter SiO₂ and Al₂O₃ particles as active particles (AP) introduced and six UCS-AP diagrams are drawn, any of which is traced to a specific amount of zeolite. Afterwards, UCS is plotted against 1/AP and η/AP which is regarded as a controlling parameter of UCS. As a consequence, for each of the zeolite–cement–sand mixtures studied, a target UCS value could be obtained using a specific correlation (1.5E8 η-^1.713AP^1.424, R² = 0.982) by porosity reductions, cement content rises and zeolite variations. This experimental research and key parameter AP will introduce an acceptable description of the mechanical parameters which are extensively used in the subgrade and foundation designs.