Predicting the Chloride Penetration of Sustainable Marine Concrete Using Data-driven and Multiphysics Frameworks
Presented By: Taihao Han
Affiliation: Missouri University of Science and Technology
Description: Chloride penetration in sustainable reinforced concrete (RC) is a critical parameter for predicting and preventing infrastructure failure, particularly for marine applications. However, replicating natural environments and testing in actual infrastructure is challenging, making it difficult to accurately measure chloride concentration in RC. Additionally, the complexity of concrete mixture designs and environmental parameters hinders the development of a universal model to predict chloride concentration at various concrete depths. This study develops a data-driven approach to predict chloride concentrations at different depths and chloride diffusion coefficients in marine RC made with common supplementary cementitious materials (e.g. fly ash, slag, etc.) under varied environmental conditions and exposure times (including both short- and long-term). Furthermore, the study leverages porosity obtained from thermodynamic simulations as a bridge to establish correlations between compressive strength and chloride diffusion coefficients. This approach enables a practical estimation of chloride diffusion coefficients in marine concrete based on simple compressive strength measurements.
Sulfate and Sea Water Resistance of Carbonated Low-lime Calcium Silicate Systems
Presented By: Raikhan Tokpatayeva
Affiliation: Purdue University - West Lafayette
Description: This presentation compares the seawater resistance of carbonated mortar made with a non-hydraulic calcium silicate cement (CCS) and conventional Type I portland cement (OPC). Tests followed modified ASTM C1012 procedures, with specimens immersed in artificial seawater (ASTM D1141-98) under three conditions: (a) room temperature (RT), (b) 60°C, and (c) deionized water (DI) as reference. Measurements included length change, visual inspection, SEM, TGA, and ICP-OES analyses. CCS mortar bars exposed to seawater at 60°C showed only slightly higher expansion than those at RT, remaining below 0.1% after 18 months. In contrast, OPC mortars exceeded this limit after about 3 months in seawater at RT. SEM revealed no major matrix degradation in CCS but did show surface decalcification and magnesium ingress. TGA and ICP-OES results corroborated calcium leaching and magnesium penetration observed in SEM.
Chloride Transport and Binding in Low Clinker Systems
Presented By: O Burkan Isgor
Affiliation: Oregon State University
Description: This presentation will examine chloride ingress and binding in low clinker systems. Specifically, the presentation discusses measurement of the formation factor and chloride binding. This work is then used in a multi-physics system to predict the time to corrosion. The work indicates that a large portion of sustainability is related to the service life of the concrete and the role of the service life is discussed.
Durability of Reduced Cement Content Structural Concrete with Nanosilica and Solid Air-Entraining Admixture
Presented By: Alberto Castillo
Affiliation: Purdue University - West Lafayette
Description: This study investigated the effect of colloidal nanosilica (nS) on the durability of bridge deck concrete with reduced cement content and higher water-to-cement ratios. Evaluated properties included compressive and flexural strength, water absorption, freeze–thaw resistance, and air-void parameters for both laboratory- and field-cast mixtures. Nontraditional solid air-entraining admixtures, specifically plastic microspheres, were also evaluated with respect to their influence on durability. Results showed that low-cement mixtures with nS performed comparably to traditional high-cement concretes, while microspheres further enhanced strength and selected durability characteristics.
Carbonation Resistance of Low-carbon Cements: the Achilles Heel of Blended Formulations?
Presented By: Franco Zunino
Affiliation: UC Berkeley
Description: Modern, low carbon cements incorporate one or more replacement materials that enable reducing the clinker factor. These materials are commonly pozzolanic, thus they actively react with calcium hydroxide to form hydration products to contribute to their mechanical properties and overall durability. However, a consequence of this is the reduction in buffer capacity of the system against carbonation, and thus higher carbonation rates are observed. In this session, the mechanisms originating this faster carbonation in blended cements will be discussed, and a perspective for future research areas and specification of durability requirements will be offered.
Air-Void Parameters in Fresh and Hardened Concrete from Pumping
Presented By: Tyler Ley
Affiliation: Oklahoma State University
Description: Pumping of air-entrained concrete can result in variable air content, which leads to possibly rejected concrete. This research used air volume, super air meter (SAM) number (AASHTO T 395), bulk freezing and thawing (ASTM C666/C666M), and hardened air-void analysis (ASTM C457/C457M) to investigate the air-void quality and freezing-and-thawing durability performance of concrete before and after pumping. The laboratory results show that the fresh-air testing measurements after pumping fresh concrete are not accurate indicators of the freezing-and-thawing resistance based on the hardened air-void analysis. However, testing fresh concrete prior to pumping is a better indicator of the freezing-and-thawing performance.
Linking Permeability and Resistivity Testing to Low GWP Mixtures
Presented By: Christopher Ferraro
Affiliation: University of Florida
Description: Current test methods that measure the electrical conductance or resistivity of concrete provide a rapid indication of concrete ability to resist chloride ion penetration. Although these methods do not provide a direct relationship to concrete water permeability, they have been widely accepted for assessing the durability of concrete