Open Access

The effect of the pre-wetting of expanded clay aggregate on the freeze-thaw resistance of the expanded clay aggregate concrete

,  and   
Jun 30, 2021

Cite
Download Cover

Figure 1

Lightweight aggregates differing in their diameter (from left to right: 8–16 mm, 4–8 mm, 2–4 mm) (Rashad, 2018).
Lightweight aggregates differing in their diameter (from left to right: 8–16 mm, 4–8 mm, 2–4 mm) (Rashad, 2018).

Figure 2

Automatic freezing chamber.
Automatic freezing chamber.

Figure 3

Specimen placed in compression testing machine.
Specimen placed in compression testing machine.

Figure 4

Mean differences between masses of specimens.
Mean differences between masses of specimens.

Figure 5

Compressive strength values (individual results and mean values).
Compressive strength values (individual results and mean values).

Figure 6

Compressive strength values (mean values).
Compressive strength values (mean values).

Figure 7

Relative mass losses.
Relative mass losses.

Figure 8

Relative strength decreases.
Relative strength decreases.

Figure 9

Strength of expanded clay aggregate concrete for reference specimens depending on water–cement ratio.
Strength of expanded clay aggregate concrete for reference specimens depending on water–cement ratio.

Concrete mix designs_

IA IIA IB IIB
Water added to mix [kg/m3] 151 110 178 178
Water contained in expanded clay aggregate [kg/m3] 27 68 27 68
Total water [kg/m3] 178 178 205 246
Actual w/c [-] 0.52 0.52 0.60 0.72
Expanded clay aggregate 4–8 [kg/m3] 301 342 301 342
Other ingredients acc. to tab. 1

Compressive strength values_

Compressive strength for individual series [MPa]
0 IA IIA IB IIB
Reference specimens Specimen no. 1 22.2 19.2 21.8 14.4 13.8
2 21.1 19.7 22.0 14.9 14.7
3 22.4 18.6 22.7 14.7 14.0
4 20.9 19.9 22.7 14.2 15.1
5 21.4 19.6 22.8 15.3 13.8
6 23.5 19.4 22.0 13.3 12.9
Mean 21.9 19.4 22.3 14.5 14.0
Std Dev 1.00 0.46 0.44 0.68 0.78
Specimens after freeze-thaw cycling Specimen no. 1 20.9 19.1 22.4 12.9 11.1
2 20.0 17.3 22.7 12.9 12.4
3 22.2 19.1 23.1 11.8 11.1
4 23.6 18.2 19.8 11.1 10.0
5 22.4 19.6 17.8 12.7 12.4
6 22.1 20.2 19.6 14.0 13.8
Mean 21.9 18.9 20.9 12.6 11.8
Std Dev 1.25 1.02 2.15 1.00 1.34

Initial concrete mix design_

Material Quantity
Portland cement 42.5R 344 kg/m3
Water 178 kg/m3
Sand 0–2 mm 821 kg/m3
Aggregate 2–8 mm (river pebble) 342 kg/m3
Expanded clay aggregate 4–8 mm 274 kg/m3
Fly ash 48 kg/m3 (13.9% cement mass)
Superplasticizer FM 6 max. 7.91 kg/m3 (max 2.3% cement mass)
W/C 0.52

Masses of specimens_

Masses for particular series [g]

0 IA IIA IB IIB

Before f/t cycles After f/t cycles Before f/t cycles After f/t cycles Before f/t cycles After f/t cycles Before f/t cycles After f/t cycles Before f/t cycles After f/t cycles
Specimen no. 1 5622.0 5616.6 5411.6 5405.4 5746.2 5731.8 5574.0 5554.4 5611.8 5596.0
2 5665.0 5660.0 5366.0 5358.6 5807.5 5797.6 5548.2 5531.0 5621.0 5448.0
3 5688.8 5686.8 5409.6 5399.2 5804.2 5784.8 5620.2 5602.0 5715.8 5495.1
4 5673.6 5662.8 5340.4 5332.6 5620.0 5606.0 5532.2 5514.2 5633.0 5501.4
5 5709.2 5707.2 5420.4 5415.9 5508.2 5498.8 5634.6 5617.0 5673.0 5505.8
6 5733.6 5726.6 5389.4 5383.8 5667.4 5657.6 5591.4 5575.0 5848.1 5499.0
Mean 5682.0 5676.7 5389.6 5382.6 5692.3 5679.4 5583.4 5565.6 5683.8 5507.6
Std Dev 38.5 39.0 31.0 31.6 117.0 115.2 40.0 40.0 89.3 48.2
Decrease 5.4 7.0 12.8 17.8 176.2

Relative mass losses ΔmF and strength decrements ΔfF_

0 IA IIA IB IIB
ΔmF [%] 0.09 0.13 0.22 0.32 3.08
ΔfF [%] 0.33 2.50 6.41 13.30 15.83

Aggregate moisture content check results_

Series 0 IA IIA IB IIB
Nominal moisture content [%] 0 10 25 10 25
Actual moisture content [%] 0.3 11.1 24.2 8.9 24.7
Language:
English