Hardening phenomenon of Portland cement suspensions monitored by Vicat test, isothermal calorimetry and oscillatory rheometry

Abstract

This work was conducted to evaluate the hardening phenomenon of pastes formulated with Portland cements blended with limestone filler (CPIIF), ground blast furnace slag (CPIIE) or pozzolan (CPIIZ). Vicat test, isothermal conduction calorimetry and oscillatory rheometry were the methods used to monitor this transition. The results of Vicat test indicates the faster setting time of pozzolan cement, but no information before this time was obtained. Using isothermal calorimetry was possible to monitor the related changes to the chemical reactions since the first contact with water, and using rheometry, the rate and force of cement particles agglomeration. The main purpose of this work was not extensively explain the results of these three methods, but show that they are complementary to better explain the transition from fluid-to-solid behavior in function of different kind of mineral addition.

Sudoku of porous, injectable calcium phosphate cements – Path to osteoinductivity

“…The other standardized method to measure the setting time of CPC is Vicat needle method that involves a penetration of a standard needle into a cement paste. According to the Standard Method NM 65:2003 (equivalent to ASTM C191-13 ), the initial time of setting occurs when the needle stops at 1 mm from the bottom and the final seting time is determined when the needle stops at 38 mm (2 mm from the surface) [ 85 ].…”

Effects of CNT Dosages in Cement Composites on the Mechanical Properties and Hydration Reaction with Low Water-to-Binder Ratio

“…The induction and acceleration periods of PC00 began after an hour and twenty hours, respectively, as shown in Figure 5. The induction periods were initiated after the formation of a protective layer on the C 3 S particles [24,25] and were complete when this layer was broken and C 3 S particles were used to form C-S-H and Ca(OH) 2 , causing the hydration reaction rates to eventually slow down [26]. That is, Alite was used to form C-S-H and Ca(OH) 2 , and the induction period was complete when the layer was broken with C 3 S particles.…”

Effect of the water/binder ratio on the hydration process of Portland cement pastes with silica fume and metakaolin

“…The hydration reactions of the cement and the release of heat are directly related to several parameters: the composition of the binder, type and content of the supplementary cementitious materials used in replacement to clinker, chemical admixture added, water/cement ratio and curing temperature. Independent of these parameters, a series of simultaneous and successive reactions are responsible for the gain of consistency or loss of workability, which generates the consolidation of suspensions and consequent resistance gain [22]. Furthermore, understand the microstructure of cement pastes is important to understand the effect of various conditions on the hydration process [23].…”