Title:
Cement Kiln Dust in Controlled Low-Strength Materials
Author(s):
Charles E. Pierce, Himanshu Tripathi, and Travis W. Brown
Publication:
Materials Journal
Volume:
100
Issue:
6
Appears on pages(s):
455-462
Keywords:
cement kiln; compressive strength; controlled low-strength cementitious material; flowable consistency
DOI:
10.14359/12951
Date:
11/1/2003
Abstract:
This paper evaluates the fluid and hardened state properties of controlled low-strength materials (CLSM) with cement kiln dust (CKD) as the primary binding agent. The low-strength property of CKD can be advantageous when used in CLSM because most applications require future excavatability. Because CLSM is often produced with fly ash (FA), it inherently mitigates the higher water demand of CKD. Laboratory-prepared mixtures with CKD:FA ratios of 1:12, 1:6, and 1:1 were investigated by varying the water-binder ratio (w/b) from 0.95 to 1.10. Flowability, volume stability (bleeding), setting time, mass density, and 28-day unconfined compressive strength (UCS) were measured for each mixture. The results revealed that high flowability and setting times within 24 h could be achieved with most mixtures, although the bleeding levels are higher than normal. Fifteen different CKD-CLSM mixtures were proportioned to produce average strengths ranging from 34 to 460 kPa. The wide range of strengths is significant for two reasons. First, all mixtures are considered to be excavatable based on these 28-day strengths. Second, the stress-strain behavior of these mixtures is representative of soil types ranging from soft clays to very stiff clays. Thus, cement kiln dust can be beneficially added to produce a very low-strength material that offers comparable strengths to soils used for conventional fills and many other low-strength applications.