Early age concrete––properties and performance

2004 ◽  
Vol 26 (5) ◽  
pp. 413-415 ◽  
Author(s):  
Konstantin Kovler ◽  
David A. Lange ◽  
Henrik Stang
Keyword(s):  
Early Age ◽  
Concrete Properties ◽  
And Performance ◽  
Early Age Concrete

Study on Failure Criterion and Yield Criterion of Early-Age C20

2012 ◽  
Vol 226-228 ◽  
pp. 1730-1734
Author(s):  
Hong Yan Ding ◽  
Chao He ◽  
Pu Yang Zhang
Keyword(s):  
Failure Criterion ◽  
Yield Criterion ◽  
Early Age ◽  
Stress Space ◽  
Concrete Properties ◽  
Function Expression ◽  
Under Construction ◽  
Early Age Concrete ◽  
Section Function ◽  
Structure Period

The early-age concrete properties are the basis for structure nonlinear analyzed under construction structure period. But at present the study on early-age concrete is lagging behind which there is not suitabel theory. This paper takes early-age C20 concrete as an example to analysis the early-age concrete properties. According to the distribution characteristics of early-age C20 concrete experiment data in the octahedral stress space, using section function expression form, by the method of mathematical derivation and linear fitting, the failure criterion and the elastic yield criterion of early-age C20 concrete materials in the octahedral stress space are established. By comparison between failure criterion and elastic yield criterion of C20 concrete, the subsequent yield criterion could be derived based on the non-uniform isotropic strengthening criterion.

Very early age concrete hydration characterization monitoring using piezoceramic based smart aggregates

2013 ◽  
Vol 22 (8) ◽  
pp. 085025 ◽  
Author(s):  
Qingzhao Kong ◽  
Shuang Hou ◽  
Qing Ji ◽  
Y L Mo ◽  
Gangbing Song
Keyword(s):  
Early Age ◽  
Concrete Hydration ◽  
Early Age Concrete

scholarly journals Mechanical and Microstructural Characteristics of Calcium Sulfoaluminate Cement Exposed to Early-Age Carbonation Curing

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3515
Author(s):  
Weikang Wang ◽  
Xuanchun Wei ◽  
Xinhua Cai ◽  
Hongyang Deng ◽  
Bokang Li
Keyword(s):  
Cement Paste ◽  
Pore Diameter ◽  
Performance Enhancement ◽  
Diameter Distribution ◽  
Early Age ◽  
Calcium Sulfoaluminate ◽  
Starting Point ◽  
And Performance ◽  
Curing Pressure ◽  
Carbonation Curing

: The early-age carbonation curing technique is an effective way to improve the performance of cement-based materials and reduce their carbon footprint. This work investigates the early mechanical properties and microstructure of calcium sulfoaluminate (CSA) cement specimens under early-age carbonation curing, considering five factors: briquetting pressure, water–binder (w/b) ratio, starting point of carbonation curing, carbonation curing time, and carbonation curing pressure. The carbonization process and performance enhancement mechanism of CSA cement are analyzed by mercury intrusion porosimetry (MIP), thermogravimetry and derivative thermogravimetry (TG-DTG) analysis, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results show that early-age carbonation curing can accelerate the hardening speed of CSA cement paste, reduce the cumulative porosity of the cement paste, refine the pore diameter distribution, and make the pore diameter distribution more uniform, thus greatly improving the early compressive strength of the paste. The most favorable w/b ratio for the carbonization reaction of CSA cement paste is between 0.15 and 0.2; the most suitable carbonation curing starting time point is 4 h after initial hydration; the carbonation curing pressure should be between 3 and 4 bar; and the most appropriate time for carbonation curing is between 6 and 12 h.

scholarly journals Characterization of Moisture Diffusion in Cured Concrete Slabs at Early Ages

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Xiao Zhang ◽  
Hongduo Zhao
Keyword(s):  
Process Model ◽  
Model Simulation ◽  
Moisture Diffusion ◽  
Experimental Results ◽  
Concrete Slabs ◽  
Model Parameters ◽  
Early Age ◽  
Water Curing ◽  
Early Age Concrete

The objective of this paper is to investigate the characterization of moisture diffusion inside early-age concrete slabs subjected to curing. Time-dependent relative humidity (RH) distributions of three mixture proportions subjected to three different curing methods (i.e., air curing, water curing, and membrane-forming compounds curing) and sealed condition were measured for 28 days. A one-dimensional nonlinear moisture diffusion partial differential equation (PDE) based on Fick’s second law, which incorporates the effect of curing in the Dirichlet boundary condition using a concept of curing factor, is developed to simulate the diffusion process. Model parameters are calibrated by a genetic algorithm (GA). Experimental results show that the RH reducing rate inside concrete under air curing is greater than the rates under membrane-forming compound curing and water curing. It is shown that the effect of water-to-cement (w/c) ratio on self-desiccation is significant. Lower w/c ratio tends to result in larger RH reduction. RH reduction considering both effect of diffusion and self-desiccation in early-age concrete is not sensitive to w/c ratio, but to curing method. Comparison between model simulation and experimental results indicates that the improved model is able to reflect the effect of curing on moisture diffusion in early-age concrete slabs.

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