MAT-712: MICROSTRUCTURAL INVESTIGATIONS ON THE SELF-HEALING ABILITY OF ENGINEERED CEMENTITIOUS COMPOSITES INCORPORATING DIFFERENT MINERAL ADMIXTURES

The present study investigates the impacts that self-healing has on the microstructure characteristics of microcracked Engineered Cementitious Composites (ECC). These have two contrasting maturity levels and, furthermore, they involve three varying mineral admixtures that have very different chemical constituents. The impact of self-healing on the transport characteristics was examined by employing rapid chloride permeability tests (RCPT). The findings indicated that, if the appropriate mineral admixture type and conditioning were chosen, it would be possible to enhance the majority of the chloride ion penetrability levels following a 30-day period of water curing. As a result, the majority of the findings were in range of the low penetrability level over the 30 days, as set by ASTM C1202. The microstructural indications corroborated the findings from the experiments and provided weight to the notion that the causal factor of the healing was the appearance of calcium carbonate and C-S-H. These served to fill the crack owing to the hydration of the cementitious particles. In summary, the results indicate that the degree of self-healing is subject to variance in accordance with the contrasting chemical compositions that dominate within a certain infrastructure type over the course of its service life

Characterization and life cycle assessment of geopolymer mortars with masonry units and recycled concrete aggregates assorted from construction and demolition waste

YesDeveloping a fast, cost-effective, eco-friendly solution to recycle large amounts of construction and demolition waste (CDW) generated from construction industry-related activities and natural disasters is crucial. The present investigation aims to offer a solution for repurposing CDW into building materials suitable for accelerated construction and housing in developing countries and disaster-prone areas. Feasibility of recycled concrete aggregate (RCA) inclusion in geopolymer mortars constituted entirely from CDW (masonry elements) was investigated via an environmental impact-oriented approach by addressing the composition related key parameters. Mechanical performance was evaluated through compressive strength tests, and scanning electron microscope (SEM) imaging with line mapping analyses were carried out to monitor the interfacial transition zone (ITZ) properties. To investigate the environmental impacts of the geopolymer mortars and highlight the advantages over Portland cement-based mortars, a cradle-to-gate life cycle assessment (LCA) was performed. Findings revealed that roof tile (RT)-based geopolymer mortars mainly exhibited better strength performance due to their finer particle size. Mixtures activated with 15 M NaOH solution and cured at 105 °C achieved an average compressive strength above 55 MPa. RCA size was the most influential parameter on compressive strength, and a smaller maximum RCA size significantly increased the compressive strength. Microstructural analyses showed that the ITZ around smaller RCAs was relatively thinner, resulting in better compressive strength results. LCA proved that CDW-based geopolymer mortars provide the same compressive strength with around 60% less CO2 emissions and similar energy consumption compared to Portland cement-based mortars.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 894100. The authors also wish to acknowledge the support of the Scientific and Technical Research Council of Turkey (TUBITAK) provided under project: 117M44

De-icing Salt Scaling Resistance of Mechanically Loaded Engineered Cementitious Composites

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84859/1/De-iceArticle.pd

Durability of Mechanically Loaded Engineered Cementitious Composites under Highly Alkaline Environment

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84845/1/Alkali-proof.pd

Engineered Cementitious Composites: An Innovative Concrete for Durable Structure

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84763/1/Durable_and_sust_OL_w_ECC_official.pd

Development of high-volume low-lime and high-lime fly-ash-incorporated self-consolidating concrete

The current article presents an experimental study on the use of two types of fly ash ( low lime and high lime) as mineral admixtures in producing self-consolidating concrete (SCC) with the objective of assessing the effects of both types of fly ash on the fresh and hardened properties of SCCs. Within the scope of an experimental programme, SCCs were prepared by keeping the total mass of cementitious materials constant at 500 kg/m(3), in which 30, 40, 50, 60 or 70% of cement, by mass, was replaced by high-lime and low-lime fly ash. The workability-related fresh properties of SCCs were observed through slump flow time and diameter, V-funnel flow time, L-box height ratio, GTM sieve stability test and the rheological parameters ( relative yield stress and relative plastic viscosity). Setting times and temperature rise of SCCs were also determined as part of fresh properties. The hardened properties that were monitored for a year included the compressive strength, ultrasonic pulse velocity, drying shrinkage and chloride permeability. It was observed that the geometry and surface characteristics of fly ash affected the workability properties of SCC mixtures. Nonetheless, the compressive strength of SCC mixtures with 30 - 40% low-lime fly ash replacement was slightly greater than the control SCC mixture at the end of the year, as the amount of fly ash replacement increased losses in compressive strength. As a result of this experimental study, it could be concluded that SCCs incorporating a fly ash replacement of 70% could be produced with improved fresh and permeation properties and sufficient compressive strength

Effect of Cracking and Healing on Durability of Engineered Cementitious Composites Under Marine Environment

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84776/1/molipaper12007.pd