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

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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 

 

 

Table 3: Characterization of cement compositions.  

Nos Cement 

compositions  Na

2

O – content %, by mass 

Al

2

O

3

 / SiO

2

 

1 

portland cement + H

2

O  

0.60 

0.242 

2 

portland cement+MK +H

2

O 0.51 

0.366 

3 

portland cement + SG  

1.70 

0.210 

4 

portland cement+MK+ SG  

1.61 

0.325 

 

 

3.2  Interfacial transition zone  

The presence of active Al

2

O

3

 intensifies structure formation processes in the interfacial 

transition zone “cement stone – aggregate”. This is confirmed by the results of studies of 

physico-mechanical characteristics of the interfacial transition zones and visual observation of 

changes in it state on the model system “cement–basalt bar”. 

 

Microphotos of the interfacial transition zones show flow of destructive processes in case of 

portland cement without metakaolin additive (Fig 1). 

 

 

Figure 1: Microphotos of the interfacial transition zone of the model system “cement stone   

basalt bar”: 1 – cement stone; 2 – interfacial transition zone; 3 – basalt bar. 

a – cement composition: “portland cement + water”; b – cement composition: “portland 

cement + soluble glass (

s 

= 2.87;   = 1300 kg/m

3

)” 

 

It is clearly seen that the interfacial boundary has lost its geometry and clearness as compared 

to its primary state, the edges of basalt are “eaten” (eroded), and the interfacial transition zone 

is rather wide and filled with products of corrosion of whitish colour. Microcracks stretching  

in the direction perpendicular to basalt aggregate and which are evidently caused by the 

increasing pressure in the interfacial transition zone are clearly visualized in the body of 

cement stone. The metakaolin additive somewhat changes picture for better (Fig. 2). No 

microcracks are seen. The products of corrosion are present but in lower quantities and edges 

of the basalt aggregate are more clear and not so heavily eroded (“eaten”) by corrosion, as in 

the first case. 

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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 2:  Microphotos and elemental distribution in the interfacial transition zone of the 

model system “cement stone   basalt bar”: 1 – cement stone; 2 – interfacial transition zone; 3 

– basalt bar.  

a – cement composition: “portland cement + metakaolin + water”; b – cement composition: 

“portland cement + metakaolin + soluble glass ( s=2.87;   = 1300 kg/m

3

)” 

 

 

4.  Structure formation processes in the interfacial transition zone. 

 

In compliance with the data of X-ray analysis, a phase composition of the hydrated 

dispersions in the interfacial transition zone of the concrete made with the cement 

composition 1 (Table 2) is represented briefly (Fig. 3, Curve 2), by the following reaction 

products: 

6

S

3

H (d = 0.335; 0.284; 0.246; 0.237; 0.225; 0.180 nm), 

2

SH (d =0.284; 0.270; 

0.246; 0.190; 0.180 nm), 

3

S

2

H (d = 0.560; 0.284; 0.184 nm), 

(

)

2

 (d = 0.487; 0.311; 

0.261; 0.193; 0.180 nm), 

3

 (d = 0.303; 0.229; 0.210; 0.193; 0.188 nm). Weak lines of 

the phase corresponding to the 

2

4

 type (d = 0.717; 0.376; 0.266; 0.258; 0.246 nm) were 

identified. An X-ray amorphous phase of the calcium silicate gel, which can be formed in the 

interfacial transition zone and to weaken it, was not identified in the X-ray pattern. However, 

judging by the elemental distribution in the interfacial transition zone and with account of a 

relatively high value of expansion (+0.44 mm/m), this possibility may exist and is supported 

to a great extent by the increased contents of 

 and Si in the interfacial transition zone. As it 

is seen from the microphotos, the interfacial transition zone is not clear, thus supporting this 

assumption. 

 

The use of the alkali activated portland cement (Table 2, Composition 3) results in changes in 

the diffraction picture of the model of the interfacial transition zone (Fig. 3, Curve 5). So, the 

hydration of the cements deepens, what is seen from the reduction of intensity of the initial 

diffraction lines. A re-distribution of the phase formation in the direction of synthesis of the 

more low-basic calcium silicate hydrates CSH(I) (d = 0.283; 0.270; 0.247; 0.179 nm), 

tobermorite (d = 0.560; 0.307; 0.299; 0.283; 0.227; 0.208; 0.183 nm) types takes place. The 

lines corresponding to 

(

)

2 

are completely absent. This allowed to make a conclusion 

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