TY - JOUR

T1 - Early hydration and microstructure formation of Portland cement paste studied by oscillation rheology, isothermal calorimetry, 1H NMR relaxometry, conductance and SAXS

AU - Bogner, A.

AU - Link, J.

AU - Baum, M.

AU - Mahlbacher, M.

AU - Gil-Diaz, T.

AU - Lützenkirchen, J.

AU - Sowoidnich, T.

AU - Heberling, F.

AU - Schäfer, T.

AU - Ludwig, H.-M.

AU - Dehn, F.

AU - Müller, H.S.

AU - Haist, M.

N1 - Funding Information: The funding of Deutsche Forschungsgemeinschaft provided to Michael Haist, Thorsten Schäfer and Michael Ludwig under the grants HA 7917/3-1 , SCHA 1854/4-1 and LU 1652/32-1 is gratefully acknowledged. Harald Müller gratefully acknowledges the funding of 1 Deutsche Forschungsgemeinschaft for the SAXS instrument under the grant INST 121384/71-1 FUGG . Harald Müller and Michael Haist gratefully acknowledge the funding of the Helmholtz Association within the Programme EMR for support in the SAXS measurements. The authors further thank Wittekind Hugo Miesbach Söhne KG for providing the cement.

PY - 2020/4

Y1 - 2020/4

N2 - An open question in predicting the rheological properties of cement suspensions has been whether changes of rheology during hydration are merely a result of shifts in the electrostatic interaction patterns of the particles over time, or whether and to which extent steric bridging by hydration products occurs. The latter could explain phenomena such as thixotropy. In this context, parallel investigations using both rheological tests and isothermal calorimetry, 1H NMR relaxometry, conductance and small-angle X-ray scattering (SAXS) measurments were carried out. It could be shown that as early as approx. 2.5 h after water addition at approx. 30 °C, small amounts of Calcium Silicate Hydrate (C-S-H) form which may contribute to a bridging of the cement particles. This phase is followed by rapid C-S-H formation, leading to a non-linear increase in paste stiffness. This phase ends with percolation, i.e. the paste stiffness increases dramatically, simultaneously with the formation of gel pore like structures, which could be observed using NMR.

AB - An open question in predicting the rheological properties of cement suspensions has been whether changes of rheology during hydration are merely a result of shifts in the electrostatic interaction patterns of the particles over time, or whether and to which extent steric bridging by hydration products occurs. The latter could explain phenomena such as thixotropy. In this context, parallel investigations using both rheological tests and isothermal calorimetry, 1H NMR relaxometry, conductance and small-angle X-ray scattering (SAXS) measurments were carried out. It could be shown that as early as approx. 2.5 h after water addition at approx. 30 °C, small amounts of Calcium Silicate Hydrate (C-S-H) form which may contribute to a bridging of the cement particles. This phase is followed by rapid C-S-H formation, leading to a non-linear increase in paste stiffness. This phase ends with percolation, i.e. the paste stiffness increases dramatically, simultaneously with the formation of gel pore like structures, which could be observed using NMR.

KW - Hydration

KW - Microstructure

KW - Opus Fluidum Futurum

KW - Rheology

KW - Small-angle X-ray scattering

UR - http://www.scopus.com/inward/record.url?scp=85078180010&partnerID=8YFLogxK

U2 - 10.1016/j.cemconres.2020.105977

DO - 10.1016/j.cemconres.2020.105977

M3 - Article

VL - 130

JO - Cement and concrete research

JF - Cement and concrete research

SN - 0008-8846

M1 - 105977

ER -