Author(s): Jack Huang; Wen-Duo Yang; Her-Yung Wang
Linked Author(s):
Keywords: Rubber particles; Furnace slag; Engineering properties; Green recycled lightweight aggregate concrete (grlac); Marine engineering
Abstract: Improving the durability of marine engineering structural materials and achieving circular economy of energy saving and carbon reduction and effective use of resource materials have been the goals of the world. Lightweight aggregates are characterized by a low thermal conductivity, seismic resistance and fire resistance. This study uses the sedimentary sludge lightweight aggregate material of Taiwan and uses a densified mixture design algorithm to examine the influence of the lightweight aggregate density (normal density and 800 and 1600 kg/m3) on the concrete engineering properties under the effect of a high temperature. The mixing water content is fixed at 170 kg/m3, the W/B ratios are 0.28,0. 32 and 0.40, and the admixtures are fly ash, slag and superplasticizer; the designed lightweight aggregate concrete can meet the requirements of a high workability, and the cement content and mixing water consumption are reduced to improve the economy and durability. The heating rate of the high-temperature furnace is fixed at 4°C/min, and three temperatures (250,500, and 750°C) and two delay times (1 h and 2 h) are used for the fire-damage tests. Compared with room temperature conditions (25°C), the changes in engineering properties are examined, and SEM testing is conducted to observe the microstructural changes under the effect of a high temperature. The findings show that the densified mixture design algorithm can provide high-flow Sedimentary sludge lightweight aggregate concrete (SSLAC). Lightweight aggregate concrete under the effect of a high temperature still has a high compressive strength residual ratio (56~99%), resistivity residual ratio (40~93%) and ultrasonic pulse velocity residual ratio (45~86%). The crack width is 86~398 μm, but the sulfate resistance is poor; after the specimen is heated, the initial temperature is low, and the thermal insulating properties are good. Lightweight aggregate concrete still has good engineering properties under the effect of a high temperature and is suitable for fire-resistant buildings, but the durability problem resulting from micro cracks requires further study. The research results can be used to solve a large number of industrial by-products, to achieve the circular economy of energy conservation and carbon reduction and environmental sustainability goals.
Year: 2020