Thermal Conductivity of Controlled Low Strength Material (CLSM) Made Entirely from By-Products

Abstract

Various by-products generated from thermal power plants and chemical industries have considerably economic and environmental impacts in South Korea. This study focuses on evaluating thermal conductivity of controlled low strength material (CLSM) made entirely from by-products (e.g., coal ash, gypsum, red mud). In the experimental program, pond ash is used as a full replacement of natural sand whereas fly ash activated by a little lime, red mud, and gypsum is the main binder in the production of CLSM. Various laboratory tests including flowability, bleeding, initial setting time, and unconfined compressive strength were performed on the prepared CLSM mixtures to determine its general characteristics. Thermal conductivity is then measured subjected to saturated curing condition (SC) and room temperature curing condition (RTC). As a result, all general characteristics meet the specification of CLSM reported in ACI 229R by controlling the ratio of gypsum to red mud. In particular, the good flowability of higher than 20 cm is observed as the G/Rm ratio of smaller than 1.33. The bleeding values, ranging from 0.30% to 2.70%, fall into the bleeding requirement of CLSM of less than 5%. Moreover, the initial setting time and strength results are also in the acceptable specification of general CLSM in ACI 229R. Eventually, the thermal conductivity of the proposed CLSM was in the range of 0.84–0.87 (W/mK) and these values were considerably affected by the saturation states and curing conditions rather than binder proportion.

Study of the Design and Mechanical Properties of the Mix Proportion for Desulfurization Gypsum–Fly Ash Flowable Lightweight Soil

“…Due to considerations regarding material costs and environmental issues, the use of locally sourced aggregates for the preparation of flowable fly ash has gained widespread attention. Researchers such as Do et al [29] have studied the use of ponded ash (PA) and excavated soil (ES) as aggregates, and experimental results show that the compressive strength and fluidity of flowable fly ash decrease while the initial setting time lengthens with a decrease in the PA/ES ratio. Tuerkel [30] prepared flowable fly ash by adding limestone sand with particle sizes of 0-5 mm, and the results showed that as the limestone sand content increased, the water absorption of the flowable fly ash increased.…”

The Effect of Baghouse Dust from Secondary Aluminum Processing Waste on Cement Hydration and Mechanical Properties

“…It is unanimously reported that the demand for portland cement and concrete, which are the most critical construction materials, has been significantly accelerating due to the global urbanization taking place over the world [1][2][3][4][5]. In 2021, 92 million metric tons of portland cement were produced in the U.S. and a total of 4.4 billion tons were manufactured worldwide [6].…”

Investigation on the impact of curing conditions on the behavior of controlled low-strength material as basement of rural roads in the Mekong Delta

“…Researchers from several fields have investigated the development of CLSM utilizing by-product material [5,6,[9][10][11]. However, there is a lack of research focus on the incorporation of curing conditions on the strength of this material.…”