Publications by authors named "Jeong-Bae Lee"

The global construction industry faces increasing pressure to adopt sustainable practices, particularly in reducing cement-related CO emissions. This study investigates the feasibility of using treated wastewater sludge (WWS) as a partial replacement for cement in repair mortars. Treated (A-WWS) and untreated (B-WWS) sludge were evaluated for their effects on workability, mechanical strength, durability, and environmental impact.

View Article and Find Full Text PDF

This paper presents an experimental study aimed at improving the performance of polymer cement mortar by evaluating the properties of acrylic ester redispersible polymers, synthesized using a change in polymerization method from emulsion monomer to monomer dropwise addition methods, along with the use of a functional additive in the form of a foaming agent. To achieve the research objectives, a polymer with a glass transition temperature of -11 °C was synthesized by fixing the monomer ratio, particle-size distribution, and glass transition temperature, and the physical properties of the polymer cement mortar were assessed. The results showed that polymers synthesized using the modified polymerization method increased elongation at break and possessed a 35% smaller average particle size.

View Article and Find Full Text PDF
Article Synopsis
  • This study investigates the use of charcoal as an expansive agent in grout to minimize pre-hardening shrinkage in cementitious materials, comparing its effectiveness to the conventional agent CSA.
  • Results showed that higher charcoal incorporation led to an increased pre-hardening expansion rate, demonstrating its superior performance over CSA in this regard.
  • However, the use of charcoal resulted in reduced compressive strength post-hardening, highlighting the importance of carefully managing the amount of charcoal used and indicating a need for additional research on charcoal's pore characteristics.
View Article and Find Full Text PDF

The cement industry emits a significant amount of carbon dioxide (CO). Therefore, the cement industry should recycle the emitted CO. However, sequestration by carbonation in cement composites absorbs a very small amount of CO.

View Article and Find Full Text PDF
Article Synopsis
  • High temperature conditions, such as fire, negatively impact the mechanical and chemical properties of concrete, prompting the development of a new coarse aggregate called PCM/SiC composite aggregate (EA) to improve fire resistance.
  • Various tests, including compressive strength, static modulus of elasticity, XRD, and SEM, were conducted to validate EA's effectiveness as a construction material, showing better residual performance after exposure to high temperatures (up to 1000 °C).
  • Results indicated that concrete with EA maintained a higher percentage of residual compressive strength and exhibited stable cement composites post-heating, unlike plain concrete, making EA a promising solution for enhancing concrete's fire resistance.
View Article and Find Full Text PDF

To solve the problem of black ice, many studies are being carried out. The key in recent days is enhancing the thermal conductivity of concrete. In this study, to improve the thermal conductivity, silicon carbide was used to substitute 50% and 100% of the fine aggregate.

View Article and Find Full Text PDF

Increasing use of cement in the construction industry is causing an alarming increase in carbon dioxide (CO) emissions, which is a serious environmental threat, it can be reduced by the addition of supplementary cementitious materials (SCMs). The commonly used SCMs like ground granulated blast furnace slag (GGBS), metakaolin (MK) and fly ash (FA) have been successfully used to replace the cement partially or completely. Polysilicon sludge obtained from the photovoltaic industry is also a type of waste material that can be used as SCM because it has high content of reactive SiO.

View Article and Find Full Text PDF

Globally, concrete is the most widely used construction material. The composition of concrete plays an important role in controlling its overall performance. Concrete is composed of approximately 70%-80% aggregates, by volume.

View Article and Find Full Text PDF

The depletion of natural sand and production of the huge amount of cement in the construction industry are serious threats to the environment, which can be reduced by the utilization of by-products as cement replacement material. In this study, cement was replaced with fly ash up to 45% (by weight). In addition, the natural fine aggregate was replaced with air-cooled blast furnace slag aggregate (here referred to as "slag aggregate") at a level of 50% and 100% (by weight).

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_sessionkk3kvh4a7lhb5be2531nc4p2mont010c): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once