TY - JOUR A1 - Mezhov, Alexander A1 - Goncharov, A. A1 - Zhutovsky, S. A1 - Kovler, K. A1 - Diesendruck, Ch. E. T1 - The Impact of DNA as a Chemical Admixture for Cementitious Materials N2 - Viscosity modifying agents (VMA) and superplasticizers (SP) are two common macromolecular admixture types for cementitious materials. VMAs are used to stabilize fresh cementitious materials, while SPs are used to disperse them. Most VMAs are bio-based polysaccharides that act in the water phase between particles; while most SPs are synthetic comb polymers, consisting of negatively charged backbones that help their adsorption to the cement particles' surface. The molecular structure of DNA contains elements of VMA – as it is a polysaccharide – and SP – as it is a polyanion. In this study, rheological measurements are used to compare how these three types of macromolecules (VMA, SP, and DNA) affect cementitious materials. It is found that DNA shows the combined effects of VMAs and SPs on cement paste: it lowers yield stress while at the same time maintaining or even increasing its viscosity, which permits reducing water content while avoiding bleeding or segregation of samples. Yet, the presence of DNA has a significant retardation impact on cement hydration, which is also a common side effect of VMAs and SPs. KW - Impact of DNA KW - Viscosity modifying agents (VMA) KW - Superplasticizers (SP) PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638542 DO - https://doi.org/10.1002/admt.202500073 SN - 2365-709X VL - 10 IS - 14 SP - 1 EP - 8 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-63854 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mezhov, Alexander A1 - Kulisch, D. A1 - Goncharov, A. A1 - Zhutovsky, S. T1 - A Comparative Study of Factors Influencing Hydration Stoppage of Hardened Cement Paste N2 - There is no consensus on which hydration stoppage method is optimal to preserve the microstructure and mineral composition of samples, especially considering the specific aspects of different testing methods, such as TGA, MIP, or XRD. This paper presents a quantitative comparison between the most popular hydration stoppage strategies and parameters such as the sample piece size, the soaking time in a solvent, and the type, as examined on cement paste hydrated for 7 days. It was found that the carbonation appears either for samples smaller than 2.36 mm and bigger than 4.75 mm or samples soaked in a solvent for longer than 1 h. Fast solvent replacement leads to ettringite diminution and total pore volume increase. Among others, solvent replacement with subsequent gentle heating under a vacuum was found to be the most efficient, whereas it was experimentally demonstrated that isopropyl alcohol stops hydration faster than ethanol and acetone. KW - Hydration stoppage KW - Solvent replacement KW - Soaking time KW - Sample piece size PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582430 DO - https://doi.org/10.3390/su15021080 VL - 15 IS - 2 SP - 1 EP - 21 PB - MDPI CY - Basel, Switzerland. AN - OPUS4-58243 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -