Modification of CO2 capture and pore structure of hardened cement paste made with nano-TiO2 addition: Influence of water-to-cement ratio and CO2 exposure age

2021 ◽  
Vol 275 ◽  
pp. 122131
Author(s):  
Carlos Moro ◽  
Vito Francioso ◽  
Mirian Velay-Lizancos
Keyword(s):  
Pore Structure ◽  
Co2 Capture ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Nano Tio2 ◽  
Cement Ratio ◽  
Exposure Age ◽  
Water To Cement Ratio ◽  
Influence Of Water ◽  
Tio2 Addition

Quantitative Characterization of Effective Porosity in Cement-Based Composite Materials

2010 ◽  
Vol 163-167 ◽  
pp. 3174-3179
Author(s):  
Guo Wen Sun ◽  
Jin Yang Jiang ◽  
Yun Sheng Zhang ◽  
Cai Hui Wang
Keyword(s):  
Composite Materials ◽  
Cement Paste ◽  
Pore Diameter ◽  
Effective Porosity ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Pore Characteristics ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Second Peak

The method of the second intrusion mercury in MIP was used to investigate the pore characteristics of hardened cement paste with w/c ratio 0.23, 0.35 and 0.53, respectively, in order to research the quantitative relationship between transport properties and pore characteristics in cement-based composite materials. The results show the second intrusion mercury could well determine the effective pore structure parameters, and effective porosity accounts for 25% to 50% of total porosity in cement paste. At the same time, the existence of the first and second peak in pore size distribution curves is confirmed by MIP, such as, the first peak in hardened cement paste with water to cement ratio 0.53 is very distinct, however, with the decrease of water to cement ratio, the first peak gradually disappears. The pore diameter corresponding to the first and second peak is critical pore diameter of capillary pore and gel pore, respectively.

Influence of Water Cement Ratio and Curing on the Permeability and Structure of Hardened Cement Paste and Concrete

1988 ◽  
Vol 137 ◽  
Author(s):  
Herbert Gräf ◽  
Max J. Setzer
Keyword(s):  
Pore Structure ◽  
Structural Changes ◽  
Early Stage ◽  
Mercury Porosimetry ◽  
Nitrogen Adsorption ◽  
Systematic Research ◽  
Hardened Cement ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Influence Of Water

AbstractCuring affects sincerely the durability of concrete especially in surface regions. This is reflected in the pore structure and in the permeability. In a systematic research the structural changes due to water cement ratio and curing have been studied by mercury porosimetry, by nitrogen adsorption, by oxygen diffusion and by oxygen permeability. Due to these results diffusion and permeability are connected by a power law. Structural changes alter the permeability by four orders of magnitude. The results can be well explained by pore size distribution both for hcp and for concrete. Carbonation and frost action as well as strength and elastic modulus are closely correlated to permeability and therefore to pore structure. For practical application it is possible to give advice for concreting and curing. Service life can be predicted by permeability measurements in an early stage. The results are comparable with Nyames /20/.

An Experimental Study of Water in Pore System of Hardened Cement Paste by Magnetic Resonance

2013 ◽  
Vol 539 ◽  
pp. 14-18
Author(s):  
An Ming She ◽  
Wu Yao ◽  
Wan Cheng Yuan
Keyword(s):  
Cement Paste ◽  
Water Distribution ◽  
Transverse Relaxation Time ◽  
Bimodal Distribution ◽  
Early Age ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Initial Water ◽  
Cement Ratio ◽  
Water To Cement Ratio

The water distribution in hardened cement paste with different ages, water to cement ratio (w/c) and different cured methods were investigated by low field NMR. The transverse relaxation time, T2, was used as a parameter to describe the water phase constrained in pores. The results show that the T2 distributions of pastes in the early age are bimodal distribution. As the curing time increase, the T2 distribution peaks shift gradually to the short T2 values reflecting the decrease of mean pore dimension as well as the increase of specific surface area resulted from the gel products. In addition, the influences of initial water to cement ratio and cure methods on water distribution are occurred mainly during the early age. When cured to 28 days, the differences of water distribution in various samples are unconspicuous.

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