<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>The internal pore structure of sulphoaluminate cement concrete (SACC) significantly affects its mechanical properties. The main purpose of this study was to establish the relationship between pore structure changes and compressive strength after exposure to elevated temperatures. SACC samples that had been cured for 12 months were dried to a constant weight and then exposed to different temperatures (100 °C, 200 °C and 300 °C), after which the compressive strength and pore structure were measured. The pore structure of SACC was quantitatively described by mercury intrusion porosimetry (MIP) and nitrogen adsorption results. The results showed that with increased temperature, the porosity of the SACC samples also increased and the pore structure was gradually destroyed. Moreover, the SACC’s compressive strength gradually decreased with increasing temperature. The relationship between compressive strength and porosity was in close agreement with the compressive strength–porosity equation proposed by Schiller. Therefore, after extensive exposure to elevated temperature, the changes in SACC’s compressive strength can be quantitatively described by the Schiller equation.</p>
</abstract>

The internal pore structure of sulphoaluminate cement concrete (SACC) significantly affects its mechanical properties. The main purpose of this study was to establish the relationship between pore structure changes and compressive strength after exposure to elevated temperatures. SACC samples that had been cured for 12 months were dried to a constant weight and then exposed to different temperatures (100 °C, 200 °C and 300 °C), after which the compressive strength and pore structure were measured. The pore structure of SACC was quantitatively described by mercury intrusion porosimetry (MIP) and nitrogen adsorption results. The results showed that with increased temperature, the porosity of the SACC samples also increased and the pore structure was gradually destroyed. Moreover, the SACC’s compressive strength gradually decreased with increasing temperature. The relationship between compressive strength and porosity was in close agreement with the compressive strength–porosity equation proposed by Schiller. Therefore, after extensive exposure to elevated temperature, the changes in SACC’s compressive strength can be quantitatively described by the Schiller equation.

The impact of changes in pore structure on the compressive strength of sulphoaluminate cement concrete at high temperature

School of Materials Science and Engineering

Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials

Materials Science-Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

The internal pore structure of sulphoaluminate cement concrete (SACC) significantly affects its mechanical properties. The main purpose of this study was to...

Temperature (°C)	Average Micropore porosity (ml/g)	Average threshold diameter (nm)	Most probable pore size (nm)	Average peak value (ml/g)
20	0.066	9.92	5.20	0.051
100	0.055	11.96	5.50	0.042
200	0.050	13.57	5.50	0.037
300	0.043	14.49	5.20	0.032

Temperature (°C)	Average porosity (ml/g)		PHg	Threshold diameter (nm)	Most probable aperture (nm)
Temperature (°C)	Capillary pores (10 – 200 nm)	Air voids (> 200 nm)		Threshold diameter (nm)	Most probable aperture (nm)
20 (ref.)	2.89	0.20	2.98	100	27.26
100	3.30	0.60	4.76	130	59.03
200	4.38	0.90	5.53	7500	98.91
300	4.98	1.89	7.71	20000	118.40

Oxides
CaO	Al₂O₃	SO₃	SiO₂	Fe₂O₃	MgO	TiO₂	K₂O	SrO	Na₂O	Cl	P₂O₅
519.4	86.2	86.2	40.5	80.0	13.1	5.1	6.8	59.9	0.5	1.3	0.5
45.28%	17.51%	15.76%	9.19%	2.50%	1.90%	0.75%	0.48%	0.17%	0.19%0.11	%	0.10%

Temperature (°C)	Total porosity (ml/g)	Dimensionless chemically bound water loss (w_d/c)
100	9.9	0.034
200	11.9	0.075
300	14.4	0.113

Specimens types	Temperature (°C)
Specimens types	20 Ref	100	200	300
Compressive strength	51.31	39.52	37.88	28
R/%	0	22.97	26.17	45.42

The impact of changes in pore structure on the compressive strength of sulphoaluminate cement concrete at high temperature

Published Online: Jul 06, 2021

Page range: 75 - 85

Received: Feb 25, 2021

Accepted: Mar 12, 2021

DOI: https://doi.org/10.2478/msp-2021-0006

Keywords
Elevated temperature, pore structure, sulphoaluminate cement concrete, mercury intrusion porosimetry (MIP), nitrogen adsorption

© 2021 J.J.K. Tchekwagep et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Pore size distribution parameters of specimens (N2 adsorption).

Pore size distribution parameters of specimens (MIP).

Chemical proportions of cement in concrete

Mix proportions of SACC

The relationship between the total porosity of concrete and the mass loss of dimensionless chemically bound water.

Compressive strength results of the SACC

The impact of changes in pore structure on the compressive strength of sulphoaluminate cement concrete at high temperature

Published Online: Jul 06, 2021

Page range: 75 - 85

Received: Feb 25, 2021

Accepted: Mar 12, 2021

DOI: https://doi.org/10.2478/msp-2021-0006

KeywordsElevated temperature, pore structure, sulphoaluminate cement concrete, mercury intrusion porosimetry (MIP), nitrogen adsorption

© 2021 J.J.K. Tchekwagep et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Pore size distribution parameters of specimens (N2 adsorption).

Pore size distribution parameters of specimens (MIP).

Chemical proportions of cement in concrete

Mix proportions of SACC

The relationship between the total porosity of concrete and the mass loss of dimensionless chemically bound water.

Compressive strength results of the SACC

Keywords
Elevated temperature, pore structure, sulphoaluminate cement concrete, mercury intrusion porosimetry (MIP), nitrogen adsorption