• Advances in concrete construction
• /
• v.6 no.6
• /
• pp.561-583
• /
• 2018

A variety of polycarboxylate ether (PCE)-based superplasticizers are commercially available. Their influence on the rheological retention and slump loss in respect of concrete differ considerably. Fluidity and slump loss are the cardinal features responsible for the quality of concrete. These are related to the dispersion of cement particles and the hydration process which are greatly influenced by type of polycarboxylate ether (PCE)-based superplasticizers. On the backdrop of relatively less studies in the context of rheological retention of high strength self-consolidating concrete (HS-SCC), the experimental investigations were carried out aiming at quantifying the effect of the six different PCE polymers (PCE 1-6) on the rheological retention of HS-SCC mixes containing two types of Ordinary Portland Cements (OPC) and unwashed crushed sand as the fine aggregate. The tests that were carried out included $T_{500}$, V-Funnel, yield stress and viscosity retention tests. The supplementary cementitious materials such as fly ash (FA) and micro-silica (MS) were also used in ternary blend keeping the mix paste volume and flow of concrete constant. Low water to binder ratio was used. The results reveal that not only the PCEs of different polymer groups behave differently, but even the PCEs of same polymer groups also behave differently. The study also indicates that the HS-SCC mixes containing PCE 6 and PCE 5 performed better as compared to the mixes containing PCE 1, PCE 2, PCE 3 and PCE 4 in respect of all the rheological tests. The PCE 6 is a new class of chemical admixtures known as Polyaryl Ether (PAE) developed by BASF to provide better rheological properties in even in HS-SCC mixes at low water to binder mix. In the present study, the PCE 6, is found to help not only in reduction in the plastic viscosity and yield stress, but also provide good rheological retention over the period of 180 minutes. Further, the early compressive strength properties (one day compressive strength) highly depend on the type of PCE polymer. The side chain length of PCE polymer and the fineness of the cement considerably affect the early strength gain.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.28 no.2
• /
• pp.69-76
• /
• 2024

The rheological properties of fresh concrete significantly influence its manufacturing and performance. However, the diversification of newly developed mixtures and manufacturing techniques has made it challenging to accurately predict these properties using traditional empirical methods. This study introduces a multiscale rheological property prediction model designed to quantitatively anticipate the rheological characteristics from nano-scale interparticle interactions, such as those among cement particles, to micro-scale behaviors, such as those involving fine aggregates. The Yield Stress Model (YODEL), the Chateau-Ovarlez-Trung equation, and the Krieger-Dougherty equation were utilized to predict the yield stress for cement paste and mortar, as well as the plastic viscosity. Initially, predictions were made for the paste scale, using the water-cement ratio (W/C) of the cement paste. These predictions then served as a basis for further forecasting of the rheological properties at the mortar scale, incorporating the same W/C and adding the cement-sand volume ratio (C/S). Lastly, the practicality of the predictive model was assessed by comparing the forecasted outcomes to experimental results obtained from rotational rheometer.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.5
• /
• pp.880-887
• /
• 2004

This study was carried out to examine the effect of added Doenjang on wheat flour dough and gluten rheological properties using Micro-extensigraph method and correlation between factors relating with Doenjang or dough rheology and bread Quality. There were big differences in pretense activity and free amino acid contents among seven commercial Doenjangs. The addition of Doenjang to wheat flour dough required increased mixing time for gluten development. Dry gluten content increased significantly with addition of less than 5.0% of Doenjang powder. As the amount of Doenjang powder increased, dough peak force decreased and extensibility increased up to a certain level an then decreased, producing the weak dough. This phenomena was seen more obviously in wet gluten than wheat flour dough. Especially, the Doeniang having high pretense activity and high cystein content, caused highly extensible weak dough resulting in bread with high loaf volume and tender texture at the levels of 2.5% added Doenjang. Increase of dry gluten content and extensibility of wheat flour dough or wet gluten positively correlated (r=0.76, 0.91, 0.93), with loaf volume and negatively with hardness values, respectively. Therefore, it was concluded that improvement of bread quality with Doenjang resulted from increase of gluten content and dough extensibility.