Elucidating the role of water in collagen self-assembly by isotopically modulating collagen hydration

Water is known to play an important role in collagen self-assembly, but it is still largely unclear how water-collagen interactions influence the assembly process and determine the fibril network properties. Here, we use the H[Formula: see text]O/D[Formula: see text]O isotope effect on the hydrogen-bond strength in water to investigate the...

Effect of rice straw powder on properties of one-part alkali-activated slag

One-part alkali-activated slag (AAS) as a binder material has a promising application in the construction industry. The properties of one-part AAS incorporating agricultural wastes have been seldom studied. In this paper, the fresh and hardened properties of one-part AAS with the addition of rice straw powder (RSP) were investigated. The...

Effects of the fineness of densified silica fume on the hydration of Portland cement

As one of the mineral admixtures, silica fume (SF) with high pozzolanic reactivity is generally used to improve the properties of concrete. Most commercial silica fume used in concrete project is dry densified silica fume (DSF). It consists of a good deal of agglomerates of sizes ranging from 10 μm to several millimeters. The size of the...

Effect of chloride salts on sulfoaluminate cement hydration

The effect of including 5 % chloride salts (NaCl and CaCl2) on calcium sulfoaluminate cement hydration was studied. The rate of heat release, setting times and mechanical strength were determined in 2 d, 28 d and 90 d cement pastes. The hydration products formed at those ages were identified with XRD and SEM. Hydration reactions were hastened...

Modern approach to surface layer modifications of hydrated cement paste for improving permeability estimates of virtual concrete

Permeability estimates obtained by physical experiments and by simulations differ quite significantly. When biases at the experimental side would be eliminated, the expected modest gap could be bridged by surface layer modifications of the hardened cement paste, discussed herein. This involves the formation of a fractal-like nano-particle...

Re-Investigation of Hydration Potential of Rhodococcus Whole-Cell Biocatalysts towards Michael Acceptors

The implementation of a stereoselective Michael addition with water as substrate is still a major challenge by classical, chemical means. Inspired by nature's ability to carry out this attractive reaction with both high selectivity and efficiency, the interest in hydratases (EC 4.2.1.x) to accomplish a selective water addition is steadily...

Transport Processes in Hydrating Cementitious Coating Systems

Concrete is currently the most widely used material in construction field. A good performance of concrete structures is required for reaching the designed service life. However, the initial scatter in the quality of concrete is unavoidable in practice, possibly resulting from improper design, poor execution, or deterioration due to stresses...

Simulation of hydration and microstructure development of blended cements

For optimization of the use of Supplementary Cementitious Materials (SCMs), i.e. blast furnace slag (BFS) and fly ash (FA), in cementitious system a numerical model for simulating the hydration and microstructure development of blended cements can be used. Several models have been proposed in recent years to simulate the hydration and...

Demonstration and validation by simple examples of a complete analogue porosimetry methodology for virtual cement pastes on micro-level

Details of a complete methodology for porosimetry of virtual concrete have been described in a series of publications. This paper shortly sketches the main characteristics, whereupon it is indicated how a pore network model is designed based on data extracted from the virtual cement paste. This involves smoothing the main trunks as the main pore...

Packing issue in cement blending for sustainability developments - Approach by discrete element method

Common cement blending materials for concrete like fly ashes, blast furnace slag, silica fume, metakaolin and rice husk ash have been investigated experimentally as to their impact on concrete’s mechanical, physical and sustainability capabilities. Such efforts offer but case-related information on involved materials and used procedures....

Porosimetry by DraMuTS applied to DEM-produced cementitious materials

Porosimetry of matured cementitious materials is of hiigh interest, because durability is governed by the capillary pore network structure. Experimental approaches are time-consuming, laborious and thus expensive. Fast developments in computer technology make it nowadays possible quite realistically producing cementitious materials in virtual...

Analogue simulation by dem of material structure for property estimation of cementitious materials

Realistic simulation of particulate materials like concrete on meso- as well as micro-level is nowadays possible by fast developments in computer technology. This would be a more economic way than by physical experiinents, which are more time-consuming, laborious and thus expensive. This concern the production of the aggregate structure or of...

Numerical modeling of hydration process and temperature evolution in early age concrete

Heat production induced by the hydration reaction and the resulting temperature evolution in the early phases of setting and hardening processes are critical phenomena, often leading to premature cracking of concrete members. However, the interest for simulating such phenomena is also related to the fundamental relationships between the nature...

Dielectric measurements to characterize the microstructural changes of young concrete

The dielectric properties of concrete can be used to characterize the development of the microstructure of the cement paste. During hydration the microstructure changes and so does the amount of water in the pore structure. The different dielectric properties of the pore water and the solid phases can be measured with microwave frequencies. In...