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Enhancing the dynamic properties of expansive soils using cementitious materials has attracted the attention of many researchers over the past few decades. Supplementary cementitious materials (SCMs) can be used as partial substitutes for cement owing to their pozzolanic activity that further improves the mechanical performance of cement-stabilized soils upon curing. In this study, the effect of cement and zeolite incorporation on the mechanical behavior of expansive clay was quantified using the pressure wave velocity (Vp) indicator obtained from ultrasonic pulse velocity tests performed at different curing times. Furthermore, a polynomial model was developed to establish the relationship between Vp and zeolite replacement levels at specific curing times and cement contents. The results show that a polynomial function captured the decreasing trend of Vp upon the increase in zeolite at curing times below 14 days. Additionally, the developed equation explained the upward trend of Vp owing to the pozzolanic activity of zeolite at later curing times with an accuracy of over 92%. The coefficients of the polynomial model also increased with the increment of the cement percentage which conformed to the consecutive rise in Vp. Ultimately, the polynomial coefficients were expressed in terms of cement content and curing time using the Volterra series. Using this model, the optimum percentage of cement replaced with zeolite (Zopt), the efficiency of using Zopt instead of cement, and the percentage of zeolite replacement to achieve equivalent Vp of cemented clay samples (ZC) were estimated. The findings of this study contribute to promoting geotechnical sustainability by replacing cement with zeolite that has a considerably lower environmental footprint. Clay is a type of soil that can be found in many construction projects. For instance, many roads and buildings' foundations are constructed on clay soils. To ensure the necessary strength of the clay under the main structure, the soil should often be stabilized using adhesive construction materials such as cement. Interestingly, a portion of the cement could be replaced with other minerals not only to improve engineering performance but also to promote sustainability by lowering cement consumption. In this study, the effect of zeolite as a partial replacement for cement on the strength of clay soils was experimentally evaluated. The effect of various design parameters, such as cement replacement level and curing time, on the stability of clays was investigated using an advanced technique called the ultrasonic pulse velocity (UPV) test. Furthermore, a simple mathematical model was proposed based on the experimental results to help engineers design the stabilization plan and timely decide about the next steps of the construction process. [ABSTRACT FROM AUTHOR]

Corrosion is important in the design, maintenance, and preservation of bridge steel pile foundation systems. It is an inevitable phenomenon when steel is exposed to the environment, as metals tend to return to their lower energy state. While the corrosion rate of steel is predictable for atmospheric exposures, it is highly variable and difficult to predict for steel buried underground because of the high variability of soils. Applying a protective sacrificial layer is a common protection method to prevent corrosion. This study aims to evaluate the efficiency of a galvanized and painted galvanized steel bridge pile for achieving a 100-year service life and to economically compare them for using piles without a coating. To meet this objective, 21 steel coupon samples and nine 30 cm pile samples with galvanized coating, painted-galvanized coating, and no coating were tested in a cyclic corrosion test chamber to investigate the efficiency of each coating. The test was conducted for 600 days simulating a 100-year service life. Results from the experimental test revealed that galvanized and painted-galvanized coating methods show remarkable performance in protecting the piles against corrosion, and both methods can protect the piles from corrosion for 100 years. Further evaluation showed that, while the cost to increase the pile size was determined to be less than the premium for galvanizing or galvanizing and painting the piles for the bridge in this study, a cost–benefit evaluation for each protection measure is suggested, knowing that costs can vary widely depending on specific project requirements, location, market prices, etc. [ABSTRACT FROM AUTHOR]