**3.3 Mixture design procedure of cold-bonding recycling aggregate by DMDA**

The following steps can be used to provide computational basis for designing the cementbased composite mixture to produce the cold-bonding recycling coarse aggregates employing the DMDA procedure.

(1) Select proper material resource and gather material information.

This is an important step for the mix design of cement-based composite mixture for producing the cold-bonding recycling coarse aggregates. The basic quality information of the ingredients of cement-based composite is necessary for the purpose of quality control.

(2) Obtain the maximum dry loose density (i.e. unit weight) by iteratively packing recycling resources, BF slag, and fly ash in filler system.

Cold-Bonding Technique – A New Approach to Recycle

based composite mixture (kg/m3).

system, respectively (kg/m3); *water*

slag, respectively (kg/m3).

where *fiber* γ

If ξ

Innocuous Construction Residual Soil, Sludge, and Sediment as Coarse Aggregates 105

(8) Calculate the amount of cement, BF slag and mixing water in paste system:

*P V*

is the ratio of replacing cement with BF slag by weight, then:

ξ

 , *cement* γ

*cement cement <sup>p</sup>*

/ *water*

*V nV*

γ

Substitute Equation 11 into Equation 10 to obtain:

If the water-to-cementitious material ratio (w/cm) is

*w cm*

*W*

(9) Determine the dosage of SP and amount of water

*Wslag*<sup>2</sup> and *Wwater* , respectively.

λ

Using Equations 11 and 13, Equation 12 can be used to solve for *Wcement* :

*<sup>w</sup> cement*

γ

experience as shown in Equation 15 and Fig. 5 (Chang et al., 2009).

=

λ

 is the density of glass fiber (kg/m3); *Wfiber* , *Wflyash* , *Wslag*<sup>1</sup> , and *W*Re are weights of glass fiber, fly ash, BF sand, and recycling resource, respectively in the cement-

*water cement slag*2

2

1

λ, then:

*cement flyash slag slag*

<sup>1</sup> ( )

*W*

1 1 [ ( )] <sup>1</sup>

++ + <sup>−</sup>

 ξλ

*water cement water slag*

 ξγ

*p flyash slag*

*V WW*

− +

λ

The calculated *Wcement* can be substituted both into Equation 11 and Equation 13 to obtain

The dosage of SP is determined by its quality and the total water content. Under fixed total amount of water and w/cm ratio, the SP dosage can be estimated according to past

γ

 γ ξ

<sup>−</sup> = ++ (12)

ξ

1 2

 γ

SP (%)= 4.59×10-5×*X*2 – 1.81×10-2×*X*+1.98 (15)

+ ++ (13)

(14)

 γ

=⋅ = + + (10)

<sup>=</sup> <sup>+</sup> (11)

are densities of water, cement, and BF

*water cement slag*

*W W W*

2

γ

*water cement cement*

*water cement slag*

γγγ

*W W WW* = =

*slag cement slag*

*W W W*

where *Wwater* , *Wcement* , and *Wslag*2 are weights of water, cement, and BF slag in paste

, and *slag*

*<sup>W</sup> <sup>W</sup> <sup>W</sup> <sup>W</sup> <sup>W</sup> <sup>V</sup>*

γγ

(2-a) Fill fly ash with BF slag and then obtain:

$$\alpha = \frac{\mathcal{W}\_{\text{slag}}\mathbf{1}}{\mathcal{W}\_{\text{slag}}\mathbf{1} + \mathcal{W}\_{\text{flys}\text{sl}}\mathbf{1}}\,\tag{1}$$

where α is the ratio at maximum dry loose density as fly ash is filled with BF slag; 1 ' *Wslag* is the weight of BF slag (kg) in filler system; ' *Wflyash* is the weight of fly ash (kg).

(2-b) Fill recycling resource with the blend of fly ash and BF slag under fixed α, and obtain:

$$\mathcal{B} = \frac{\mathcal{W}\_{slag}\mathbf{1}' + \mathcal{W}\_{flugsk}\mathbf{'}}{\mathcal{W}\_{slag}\mathbf{1}' + \mathcal{W}\_{flugsk}\mathbf{'} + \mathcal{W}\_{\text{Re}}\mathbf{'}} \tag{2}$$

where β is the ratio at maximum dry loose density as recycling resource were filled with the blend of fly ash and BF slag; Re *W* ' is the weight of recycling resource (kg).

(3) Select the volume of glass fiber (η) added into cement-based composite.

(4) Calculate the least void, *Vv* :

$$V\_v = 1 - \sum \frac{\mathcal{W}\_i}{\mathcal{Y}\_i} - \eta \tag{3}$$

where ' *Wi* (kg/m3) and *<sup>i</sup>* γ (kg/m3) are the weight and density of *i* constituent material in filler system, respectively.

(5) Assign a lubricating paste thickness (*t*) and calculate the volume of cement paste.

$$V\_p = nV\_v \tag{4}$$

where *n* is a multiplier for lubricating paste; *Vp* is the volume of cement paste.

(6) Calculate the factor of volume variation (υ) (Tsai, 2005):

$$\upsilon = \frac{1 - \eta - nV\_v}{1 - \eta - V\_v} \tag{5}$$

(7) Calculate the weight of recycling resource, BF slag, fly ash, and glass fiber in filler system, respectively:

$$\mathcal{W}\_{\text{fiber}} = \eta \times \mathcal{Y}\_{\text{fiber}} \tag{6}$$

$$\mathcal{W}\_{\text{flysalr}} = \mathcal{U} \times \mathcal{W}\_{\text{flysalr}} \text{'} \tag{7}$$

$$\mathcal{W}\_{\text{slag}\,\mathbf{1}} = \mathcal{U} \times \mathcal{W}\_{\text{slag}\,\mathbf{1}} \,\text{'} \tag{8}$$

$$\mathcal{W}\_{\text{Re}} = \mathcal{U} \times \mathcal{W}\_{\text{Re}}\,'\,\tag{9}$$

where *fiber* γ is the density of glass fiber (kg/m3); *Wfiber* , *Wflyash* , *Wslag*<sup>1</sup> , and *W*Re are weights of glass fiber, fly ash, BF sand, and recycling resource, respectively in the cementbased composite mixture (kg/m3).

(8) Calculate the amount of cement, BF slag and mixing water in paste system:

$$\Delta V\_P = n \cdot V\_V = \frac{\mathcal{W}\_{water}}{\mathcal{Y}\_{water}} + \frac{\mathcal{W}\_{centent}}{\mathcal{Y}\_{centent}} + \frac{\mathcal{W}\_{slag}}{\mathcal{Y}\_{slag}} \tag{10}$$

If ξ is the ratio of replacing cement with BF slag by weight, then:

$$\mathfrak{L} = \frac{\mathcal{W}\_{\text{slag}\,\text{2}}}{\mathcal{W}\_{\text{cement}} + \mathcal{W}\_{\text{slag}\,\text{2}}} \tag{11}$$

where *Wwater* , *Wcement* , and *Wslag*2 are weights of water, cement, and BF slag in paste system, respectively (kg/m3); *water* γ , *cement* γ , and *slag* γ are densities of water, cement, and BF slag, respectively (kg/m3).

Substitute Equation 11 into Equation 10 to obtain:

104 Sintering of Ceramics – New Emerging Techniques

1

1

*slag flyash W W WW W*

1 *<sup>i</sup> <sup>v</sup>*

*<sup>W</sup> <sup>V</sup>*

(5) Assign a lubricating paste thickness (*t*) and calculate the volume of cement paste.

1 1

η

η

(7) Calculate the weight of recycling resource, BF slag, fly ash, and glass fiber in filler

*Wfiber fiber* = × η γ

 *W W flyash* = × υ

1 1 ' *W W slag* = × υ

Re Re *W W* = × υ

where *n* is a multiplier for lubricating paste; *Vp* is the volume of cement paste.

υ

α

the weight of BF slag (kg) in filler system; ' *Wflyash* is the weight of fly ash (kg). (2-b) Fill recycling resource with the blend of fly ash and BF slag under fixed

β

blend of fly ash and BF slag; Re *W* ' is the weight of recycling resource (kg).

η

*W W W*

1

'

' ' *slag slag flyash*

is the ratio at maximum dry loose density as fly ash is filled with BF slag; 1 ' *Wslag* is

1 Re

is the ratio at maximum dry loose density as recycling resource were filled with the

'

*v v nV V*

'

η

*i*

γ

) added into cement-based composite.

' ' ' '' *slag flyash*

<sup>=</sup> <sup>+</sup> (1)

<sup>+</sup> <sup>=</sup> + + (2)

=− − (3)

*V nV <sup>p</sup>* = *<sup>v</sup>* (4)

− − <sup>=</sup> − − (5)

(6)

*flyash* (7)

*slag* (8)

' (9)

(kg/m3) are the weight and density of *i* constituent material in

α

, and obtain:

(2-a) Fill fly ash with BF slag and then obtain:

(3) Select the volume of glass fiber (

γ

(6) Calculate the factor of volume variation (υ) (Tsai, 2005):

(4) Calculate the least void, *Vv* :

where ' *Wi* (kg/m3) and *<sup>i</sup>*

filler system, respectively.

system, respectively:

where α

where β

$$\mathcal{V}\_p = \frac{\left(\frac{\mathcal{W}\_{water}}{\mathcal{W}\_{cement}}\right) \mathcal{W}\_{cement}}{\mathcal{Y}\_{water}} + \frac{\mathcal{W}\_{cement}}{\mathcal{Y}\_{cement}} + \frac{\left(\frac{\mathcal{F}}{1-\mathcal{\xi}}\right) \mathcal{W}\_{cement}}{\mathcal{Y}\_{slag}} \tag{12}$$

If the water-to-cementitious material ratio (w/cm) is λ, then:

$$\text{aw } / \text{cm} = \mathcal{X} = \frac{\mathcal{W}\_{\text{water}}}{\mathcal{W}\_{\text{cemant}} + \mathcal{W}\_{\text{fysak}} + \mathcal{W}\_{\text{slag}}1 + \mathcal{W}\_{\text{slag}2}} \tag{13}$$

Using Equations 11 and 13, Equation 12 can be used to solve for *Wcement* :

$$\mathcal{W}\_{cement} = \frac{V\_p - \frac{\lambda}{\mathcal{Y}\_w}(\mathcal{W}\_{f;yash} + \mathcal{W}\_{slag})}{[\frac{\lambda}{\mathcal{Y}\_{water}} + \frac{1}{\mathcal{Y}\_{cement}} + \frac{\xi}{1-\xi}(\frac{\lambda}{\mathcal{Y}\_{water}} + \frac{1}{\mathcal{Y}\_{slag}})]} \tag{14}$$

The calculated *Wcement* can be substituted both into Equation 11 and Equation 13 to obtain *Wslag*<sup>2</sup> and *Wwater* , respectively.

(9) Determine the dosage of SP and amount of water

The dosage of SP is determined by its quality and the total water content. Under fixed total amount of water and w/cm ratio, the SP dosage can be estimated according to past experience as shown in Equation 15 and Fig. 5 (Chang et al., 2009).

$$\text{SP (\%)}=4.59 \times 10^{\circ} \times X^{2} - 1.81 \times 10^{\circ} \times X + 1.98 \tag{15}$$

Cold-Bonding Technique – A New Approach to Recycle

have nice properties.

Mix No.

aggregates.

Innocuous Construction Residual Soil, Sludge, and Sediment as Coarse Aggregates 107

is too small to adequately form the recycling aggregates (see Fig. 6) due to the intended cement-based composite contains lower moisture to minimize the shrinkage rate or the expansion rate and ensure the durability of cold-bonding recycling coarse aggregate. On the contrary, while the cement-based composite with higher moisture could be successfully granulated by using spirally push method, but the produced recycling aggregates will not

Cement BF slag Fly ash Recycling

Table 7. Mixture proportions of cold-bonding recycling aggregates.

Regardless of the cement-based composite contains how much moisture, the immediately squeeze out method will not successfully achieve the granulation of cold-bonding recycling coarse aggregate. This is due to the water within cement-based composite was drained out as shown in Fig. 7, like consolidation in geotechnical engineering (Holitz & Kovacs, 1981), during the process of granulating recycling coarse aggregates. Therefore the immediately squeeze out method also cannot be employed to form the cold-bonding recycling coarse

B2-3-50 50 150 235 1656 39.4 87 B2-3-100 100 110 255 1617 39.4 93 B2-3-200 200 20 280 1573 39.4 100 B3-50 50 150 235 1574 39.4 87 B3-100 100 110 255 1537 39.4 93 B3-200 200 20 280 1496 39.4 100 B4-50 50 150 235 1528 39.4 87 B4-100 100 110 255 1491 39.4 93 B4-200 200 20 280 1450 39.4 100 B6-50 50 150 235 1615 39.4 87 B6-100 100 110 255 1578 39.4 93 B6-200 200 20 280 1535 39.4 100 A-50 50 100 390 1403 39.4 108 A-100 100 70 345 1446 39.4 103 A-200 200 20 252 1522 39.4 95 B-50 50 100 385 1308 39.4 107 B-100 100 70 358 1324 39.4 106 B-200 200 20 252 1412 39.4 95 L-50 50 120 315 976 39.4 97 L-100 100 85 279 999 39.4 93 L-200 200 20 204 1047 39.4 85

Mixture proportions (kg/m3)

resource

Glass fiber SP+Water

where *X* is total amount of water (kg/m3).

Fig. 5. The SP dosage for cold-bonding recycling coarse aggregates (Chang et al., 2009).

### **3.4 Mixture of cold-bonding recycling aggregate**

According to the procedure of DMDA described in Section 3.3, the mixture proportions of cement-based composite with various recycling resources for producing the cold-bonding recycling coarse aggregates are shown in Table 7. For instance, B2-3-200 represents a cement-based composite contains the construction residual soil of B2-3 category and a cement amount of 200 kg/m3; B-100 represents a cement-based composite with B granite sludge and a cement amount of 100 kg/m3; L-50 represents a cement-based composite with lime sludge and a cement amount of 50 kg/m3.
