摘要(英) |
The
research was conducted to investigate the short term (28 days)
and long term (60 days) strength of the controlled low strength
material (CLSM) using the re-cycled materials including the
sandy soils from pipe trench excavation and bottom ash from
furnace of power plants. The sandy soil from trench excavations
was washed and sieved to exclude sizes larger than 3/8” before
the specimens were prepared with parameters of selected water
cement ratios (3.2, 2.7,2.18,1.71,1.41, and 1.1) and bottom
ash ratios (0, 20, 40, 60, 80, and 100%).
The initial setting time of the CLSM specimens tested ranged
from 12 to 36 hours which satisfy the specifications for the
field operation. The results of the tests indicate that when the
water cement ratio (w/c ratio) is less than 2.14, the 28-day
strength of the CLSM increases more significantly up to 403% of
that for w/c ratio=3.2. In addition, the 28-day strength reached
the maximum when bottom ash ratio is around 50%, which is up to
141% of that for 0%bottom ash. This implies that decreasing the
w/c ratio may be a main factor for increasing the short term
strength of the CLSM, using the test results of w/c ratios of
2.7, 1.71 and 1.1 and bottom ash ratios of 60, 80 and 100%. The
test results also indicated that the long term strength is still
under development within 60 days with an increase from 3.9% to
29.95% of the 28-day strength. The significant long term
strength development in some cases should be considered in the
practical applications of the CLSM. |