Off-spec fly ash-based lightweight aggregate properties and their influence on the fresh, mechanical, and hydration properties of lightweight concrete: A comparative study

被引：10

作者：

Balapour, Mohammad ^{[1
,2
]}

Khaneghahi, Mohammad H. ^{[1
]}

Garboczi, Edward J. ^{[3
]}

Hsuan, Yick G. ^{[1
]}

Hun, Diana E. ^{[4
]}

Farnam, Yaghoob ^{[1
]}

机构：

[1] Drexel Univ, Dept Civil Architectural & Environm Engn, Philadelphia, PA 19104 USA

[2] SusMaX LLC, Philadelphia, PA 19104 USA

[3] Natl Inst Stand & Technol, Appl Chem & Mat Div, Boulder, CO 80305 USA

[4] Bldg & Transportat Sci Div, Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA

来源：

CONSTRUCTION AND BUILDING MATERIALS | 2022年 / 342卷

基金：

美国国家科学基金会;

关键词：

Waste fly ash; Lightweight aggregate; Pore size distribution; Lightweight concrete; X-ray computed tomography; SPoRA; STRENGTH; COAL; IMPACT; PORE; SLAG;

D O I：

10.1016/j.conbuildmat.2022.128013

中图分类号：

TU [建筑科学];

学科分类号：

0813 ;

摘要：

An off-spec fly ash-based spherical lightweight aggregate (LWA), designated as Spherical Porous Reactive Aggregate (SPoRA), was manufactured through a lab pilot-scale production and its engineering properties, including specific gravity, dry rodded unit weight, water absorption, mechanical performance, and pore structure, were evaluated. Using SPoRA, lightweight concrete (LWC) samples were made and their fresh, mechanical, and hydration properties were assessed and compared with LWC samples made using two commercial LWA available in the US market. The results indicated that fine and coarse SPoRA had 72 h water absorption capacities of 16.4 % and 20.9 %, respectively, which were higher than that of the two commercial LWAs. Higher saturated surface dry specific gravity of SPoRA compared to commercial LWAs led to a higher fresh density for the corresponding LWC. Using X-ray computed tomography, large spherical type pores were observed in SPoRA similar to those in the commercial slate-based LWA. The pore size distribution of SPoRA, characterized by a dynamic vapor sorption analyzer, indicated that more than 97 % of the pores had diameters greater than 50 nm. SPoRA's average bulk crushing strength was 6.8 MPa which was smaller than commercial LWA and was potentially attributed to the differences in manufacturing processes. Nonetheless, SPoRA LWC with 28 days compressive strength of 29 MPa passed the ASTM C330 requirement and had a comparable strength with LWC prepared with the commercial LWAs indicating lesser importance for the LWA strength. SPoRA LWC had a flowability of 5 % compared to LWC prepared with commercial LWAs having flowability of >= 18 %. This observation was potentially related to the fluxing agent used in the SPoRA production. SPoRA had a 70 % degree of hydration at 12 days which was comparable with that of LWC prepared with commercial LWA.

引用

页数：13

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