Research of Pore Structure of Phosphoaluminate Cement Paste Using Nitrogen Adsorption Isotherm

2010 ◽  
Vol 129-131 ◽  
pp. 1376-1380 ◽  
Author(s):  
Ming Zhang ◽  
Zhu Ding ◽  
Peng Liu ◽  
Ming Ke Wang ◽  
Feng Xing
Keyword(s):  
Adsorption Isotherm ◽  
Pore Structure ◽  
Cement Paste ◽  
Nitrogen Adsorption ◽  
Cementitious Material ◽  
Pore Distribution ◽  
Nitrogen Adsorption Isotherm ◽  
Hydration Mechanism ◽  
Scope Of Application ◽  
Early Strength

Phosphoaluminate cement (PAC) sets quickly and develops high early strength. As a novel cementitious material, its hydration mechanism and microstructure are more complex than ordinary cement. Based on nitrogen adsorption isotherm method, investigated characteristic of adsorption isotherm of PAC paste, adsorption loop and pore distribution at different hydration period with various W/C ratio, results show that adsorption and desorption isotherm are tight relate to pore structure and pore distribution. In addition, the study analyzed the scope of application of nitrogen adsorption isotherm method on investigating pore structure of cement paste.

scholarly journals Study on Shale Adsorption Equation Based on Monolayer Adsorption, Multilayer Adsorption, and Capillary Condensation

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Qing Chen ◽  
Yuanyuan Tian ◽  
Peng Li ◽  
Changhui Yan ◽  
Yu Pang ◽  
...  
Keyword(s):  
Adsorption Isotherm ◽  
Shale Gas ◽  
Size Structure ◽  
Capillary Condensation ◽  
Critical Role ◽  
Nitrogen Adsorption ◽  
Adsorption Model ◽  
Multilayer Adsorption ◽  
Nitrogen Adsorption Isotherm ◽  
Monolayer Adsorption

Shale gas is an effective gas resource all over the world. The evaluation of pore structure plays a critical role in exploring shale gas efficiently. Nitrogen adsorption experiment is one of the significant approaches to analyze pore size structure of shale. Shale is extremely heterogeneous due to component diversity and structure complexity. Therefore, adsorption isotherms for homogeneous adsorbents and empirical isotherms may not apply to shale. The shape of adsorption-desorption curve indicates that nitrogen adsorption on shale includes monolayer adsorption, multilayer adsorption, and capillary condensation. Usually, Langmuir isotherm is a monolayer adsorption model for ideal interfaces; BET (Brunauer, Emmett, Teller) adsorption isotherm is a multilayer adsorption model based on specific assumptions; Freundlich isotherm is an empirical equation widely applied in liquid phase adsorption. In this study, a new nitrogen adsorption isotherm is applied to simultaneously depict monolayer adsorption, multilayer adsorption, and capillary condensation, which provides more real and accurate representation of nitrogen adsorption on shale. In addition, parameters are discussed in relation to heat of adsorption which is relevant to the shape of the adsorption isotherm curve. The curve fitting results indicate that our new nitrogen adsorption isotherm can appropriately describe the whole process of nitrogen adsorption on shale.

FIRST ADSORBED LAYER OF NITROGEN ON PYREX AT 77.4° K

1959 ◽  
Vol 37 (10) ◽  
pp. 1105-1113 ◽  
Author(s):  
J. P. Hobson
Keyword(s):  
Adsorption Isotherm ◽  
Adsorbed Layer ◽  
Ultrahigh Vacuum ◽  
Nitrogen Adsorption ◽  
Nitrogen Adsorption Isotherm

A measure of the nitrogen adsorption isotherm on pyrex (Corning 7740) at 77.4° K has been made for pressures above the adsorbed layer ranging from 10−3 to 10−9 mm Hg. Ultrahigh-vacuum techniques were used. Geometric adsorbing areas were 60 and 32 cm2. Coverages ranged approximately from 0.001 to 0.3 monolayer. Full equilibrium was probably not achieved but the data could be represented by the Dubinin–Radushkevich equation,[Formula: see text]for P/P0 from 10−6 to 10−11, where σ is the amount adsorbed.

Adsorption Characteristics of Natural Zeolite on Ammonia Nitrogen

2012 ◽  
Vol 599 ◽  
pp. 501-504 ◽  
Author(s):  
Wei Ping Wang ◽  
Wei Wang ◽  
Ya Qun Zhou
Keyword(s):  
Adsorption Isotherm ◽  
Natural Zeolite ◽  
Adsorption Process ◽  
Nitrogen Adsorption ◽  
Ammonia Nitrogen ◽  
Absorption Effect ◽  
Nitrogen Adsorption Isotherm ◽  
First Order ◽  
Zeolite Particle ◽  
Better Than

The experiments of ammonia nitrogen adsorption isotherm and adsorption kinetics were conducted with natural zeolite, particle size of 1～1.5 mm and 2～4 mm separately. The results show that adsorption isotherm of zeolite on ammonia nitrogen accorded with Freundlich type. The maximum adsorption of crude zeolite and fine zeolite on ammonia nitrogen are 5.83 (mg /g) and 18.38 (mg /g) respectively, which indicated that absorption effect of fine zeolite is better than crude zeolite. The adsorption process of crude zeolite on ammonia nitrogen is first-order reaction with rate constant of 0.02( g•m－2•h－1).

Effect of Fineness on the Properties of Cement Paste

2014 ◽  
Vol 629-630 ◽  
pp. 366-370 ◽  
Author(s):  
Hua Jian Li ◽  
Lu Yang ◽  
Yong Jiang Xie
Keyword(s):  
Particle Size ◽  
Pore Structure ◽  
Induction Period ◽  
Cement Paste ◽  
Linear Correlation ◽  
Influence Factors ◽  
Heat Of Hydration ◽  
Hydration Heat ◽  
Negative Linear Correlation ◽  
Early Strength

Properties of cement paste were affected significently by fineness of cement which is one of the most important influence factors. Effect of fineness on the rheology properties, strength, hydration and pore structure of cement was studied. The results showed that: plastic viscosity of the cement paste can be reduced by the increase of cement fineness to some extent. The strength of cement, especially the early strength significantly increased; heat of hydration increased, the peak of hydration heat brought forward and induction period shortened; porosity of cement paste reduced with the increase of cement fineness. There is a good negative linear correlation between characteristics particle size D (0.1) and 1 day hydration heat of three different kinds of cement. Keywords: cement; fineness; hydration; porosity

Hydration Properties of Steel Slag under Different Curing Temperatures

2014 ◽  
Vol 507 ◽  
pp. 295-299 ◽  
Author(s):  
Bo Zhang ◽  
Jin Hu ◽  
Meng Yuan Li
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
Water Content ◽  
Cement Paste ◽  
Steel Slag ◽  
Pore Distribution ◽  
Curing Temperature ◽  
Hydration Properties ◽  
Evaporable Water ◽  
Temperature Conditions

The non-evaporable water content, compressive strength, and pore distribution of steel slag paste cured under different curing temperature conditions were investigated in this paper. The non-evaporable water content of steel slag paste at early ages is obviously larger at higher curing temperature. At the age of 28 days, the non-evaporable water content of steel slag paste at normal curing temperature is close to that at high curing temperature, but the compressive strength of steel slag paste at normal curing temperature is much lower than that at high curing temperature. The pore structure of steel slag paste is much coarser than that of cement paste under the same conditions.

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