L. Wright

Effect of fly ash-gypsum blend on porosity and pore size distribution of cement pastes

Abstract Abstract This paper reports results on the porosity and pore size distribution (PSD) of cement paste containing simulated desulphurised waste (SDW). The SDW was chosen due to the variability in chemical composition of real desulphurised waste. The SDW is a combination of fly ash and gypsum. The content of fly ash in the SDW changed from 0 to 100% by weight. The water to binder ratio was 0·5. The binder consists of cement and SDW. Cement in the pastes was partially replaced with 25 wt-% SDW. The porosity and PSD of cement pastes at 28 days of curing is reported. Increasing amount of gypsum does not seem to greatly change the pore volume; however, there is tendency of obtaining coarser pore structure in the presence of gypsum. The compressive strength increases with increasing amounts of gypsum. Correlation between strength and PSD is conducted.

Early age porosity and pore size distribution of cement paste with flue gas desulphurisation (FGD) waste

AbstractThis 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.

KÜKÜRT ATIKLARI (FGD)YLE HAZIRLANAN ÇYMENTO HAMURUNUN POROZYTE VE BO?LUK ORANI DE?ERLERY ÜZERYNE ETKYLERY

This paper reports results on the porosity and pore size distribution of cement paste containing varying amounts of simulated desulphurised waste (SDW). The water to binder ratio was 0.5. The binder consists of cement and SDW. The SDW is a combination of fly ash and gypsum ranging from 0-100%. Cement in the pastes was partially replaced with 25% SDW (by weight). The porosity and pore size distribution of cement pastes at 90 days of curing is reported. Increasing the amount of gypsum up does not change the pore volume, however, there is tendency of obtaining coarser pore structure in the presence of gypsum.