Proceedings of the International rilem conference Materials, Systems and Structures in Civil Engineering 2016

397

International RILEM Conference on Materials, Systems and Structures in Civil Engineering 

Conference segment on Service Life of Cement-Based Materials and Structures 

22-24 August 2016, Technical University of Denmark, Lyngby, Denmark 

 

[24], [25]. In terms of durability, studies showed that ECat incorporation on cement-based 

materials enhances chloride and sulphate ingress resistance as well as reduces alkali-silica 

reaction occurring susceptibility [1], [21], [25]. Moreover, the high specific surface of the 

ECat with water affinity promotes a significant water absorption (about 30%, by mass), thus 

has a great potential to work as an internal curing agent in UHPFRC. Nevertheless, limited 

work has been carried out on the application of ECat in special types of concrete [15]. 

The present work aims to investigate the viability of using ECat to mitigate autogenous 

shrinkage of UHPFRC. However, this preliminary study was carried out on UHPFRC 

mixtures without fibres named as UHPC. For this purpose, it were studied two reference 

mixtures with and without silica fume incorporated in the binder  as well as other four 

mixtures with partial replacement of sand with 10%, 20%, 30% and 40% by ECat. The 

workability, the setting time, the evolution of autogenous shrinkage deformations up to 7 

days, and compressive strength (at 7 and 28 curing days) were assessed for all mixtures.  

 

 

2.  Experimental program and results 

 

2.1  Materials and procedures 

The materials used in this study were typical commercial Type I 42.5R Portland cement 

(specific gravity of  3.16 g/cm

3

), ECat generated by Portuguese refinery company (specific 

gravity of  2.69 g/cm

3

 and water absorption value of 28%, by mass), silica fume (specific 

gravity of 1.38 g/cm

3

 and solid content 50%), limestone filler (specific gravity of 2.68 g/cm

3

), 

siliceous sand (1 mm maximum aggregate size, specific gravity of 2.66 g/cm

3

 and water 

absorption value of 0.02%). A polycarboxylate type superplasticizer (Sp) of specific gravity 

of 1.08 g/cm

3

 and 40% solid content was also used. The high specific surface of the ECat 

(150 m

2

/g) [25] promotes a significant water absorption which was taken into account in the 

total water added to the mixture. Furthermore, the mixing time at the beginning of the mixing 

procedure was extended in relation to what is typical to allow the ECat saturation. Particle 

size distribution of each material can be seen in Figure 1.  

The UHPC mixtures produced were i) two references mixtures - REF, SF - which binders 

were, respectively, plain cement (c) and cement partially replaced with 10% by volume of 

silica fume (sf) and ii) four mixtures – SF+ECat10, SF+ECat20, SF+ECat30 and SF+ECat40 

– that besides the blended binder (c+sf) incorporated ECat as partial sand replace varying, 

respectively, from 10 to 40% by volume, with an increment of 10%. Limestone filler (f) was 

added to all mixtures in order to complete the aggregates granulometric curve. The water to 

binder (cement + sf) volume ratio (Vw/Vb) was kept constant for all mixtures. The 

superplasticizer dosage was adjusted when needed. The mixture proportions are listed in 

Table 1.  

Immediately after mixing, a Vicat mould [26] was filled with the mortar in order to determine 

final setting time and corrugated moulds were filled and placed in autogenous setup 

measurement. Mortar test using the flow cone (Dflow) with the same internal dimensions as 

the Japanese equipment, was carried out to characterize fresh state (see [27] for details on 

equipment and test procedures). Results of flow test and final setting time are presented in 

Table 1. Prismatic specimens (4x4x16cm

3

) were produced to assess compressive strength at 7 

and 28 days of concrete age. After demoulding the following day, test specimens were cured 

in water at 20 °C in a fog room until testing. 

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398

International RILEM Conference on Materials, Systems and Structures in Civil Engineering 

Conference segment on Service Life of Cement-Based Materials and Structures 

22-24 August 2016, Technical University of Denmark, Lyngby, Denmark 

 

 

 

Figure 1 - Particle size distribution of materials used. 

 

Table 1 - Mixture compositions of UHPC. 

                      Mixture    

Constituents 

REF  

(kg/m

3

) 

SF 

(kg/m

3

) 

SF+ 

ECat10  

(kg/m

3

) 

SF+ 

ECat20  

(kg/m

3

) 

SF+ 

ECat30  

(kg/m

3

) 

SF+ 

ECat40  

(kg/m

3

) 

Binder 

Cement (c)  

885.91 

794.90 

794.90 

794.90 

794.90 

794.90 

Silica fume (sf) 

 - 

79.49 

79.49 

79.49 

79.49 

79.49 

Aggregates 

Sand 1019.86 

1019.86 

917.88 815.89 713.90  611.92 

ECat - 

 

103.23 206.45 309.68  412.91 

Limestone Filler (f) 

311.43 

311.43 

311.43 

311.43 

311.43 

311.43 

 Water 

 

178.00 

153.76 

182.66 211.57 240.47  269.37 

 Sp 

22.00 13.75 

13.75 

13.75 

17.90 24.74 

Ratios 

ECat/sand ratio (%) 

0 

0 

10 

20 

30 

40 

Vw/Vb ratio free 

0.68 

0.68 

0.68 

0.68 

0.68 

0.68 

w/c ratio 

0.22 

0.25 

0.23 

0.27 

0.30 

0.34 

Sp/(c+sf+f) ratio (%) 

1.84 

1.20 

1.20 

1.20 

1.65 

2.46 

Fresh state 

properties 

Dflow (mm) 

280 

275 307 290 289 289 

Final setting time 

(hh:mm) 

02:55 02:40 

02:20 

02:00 01:40  01:50 

 

 

 

0

10

20

30

40

50

60

70

80

90

100

0

1

10

100

1000

10000

Cumulative

passing

volume

(%)

Particle size (micron)

Cement

Filer

Ecat

Sand

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