Revealing the influence of water-cement ratio on the pore size distribution in hydrated cement paste by using cyclohexane

Author(s):  
Andrea Bede ◽  
Ioan Ardelean
2013 ◽  
Vol 19 (5) ◽  
pp. 622-627 ◽  
Author(s):  
Jamal M. Khatib ◽  
Pritpal S. Mangat ◽  
Lee Wright

This paper is part of a wide-ranging investigation on the use of flue gas desulphurisation (FGD) waste in cement-based materials. It reports the results on the porosity and pore size distribution of cement paste containing varying amounts of simulated FGD waste. The water to binder ratio was 0.5. The binder consists of cement and simulated FGD. The FGD is a combination of fly ash and gypsum ranging from 0% to 100%. Cement in the pastes was partially replaced with 25% FGD (by weight). The porosity and pore size distribution of cement pastes was determined during the early stage of hydration. Increasing the amount of gypsum does not increase the pore volume. However, increasing the amount of gypsum in the paste leads to an increase in the threshold diameter and a decrease in the percentage of small pores in the paste, both indicating a coarser pore structure. The results of this investigation were compared with data at longer curing periods.


1988 ◽  
Vol 136 ◽  
Author(s):  
P. Bredy ◽  
M. Chabannet ◽  
J. Pera

ABSTRACTFive compositions with 10% to 50% metakaolin for cement substitution were studied. The rate of hydration was studied from the compressive strength after up to 6 months of curing and from the hydrates formed (DTA-XRD). The metakaolin addition considerably reduced portlandite content in the hydrated cement and contributed to the formation of hydrated gehlenite which is not present in OPC paste. The microstructure study (SEM) shows that pozzolanic cement pastes were less crystallized than plain pastes. Mercury intrusion was used to measure porosity of hydrated cement pastes. The porosity with blended cements was higher than that with OPC, except for 10 and 20% metakaolin substitution. Evolution of the pore size distribution was studied: the pozzolanic pastes enhance small diameters.


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