scholarly journals NUMERICAL ANALYSIS TO EVALUATE THE EFFECT OF RESTRAINED EDGE DISTANCE ON EARLY AGE CRACKING DUE TO DRYING SHRINKAGE

2019 ◽  
Vol 17 (63) ◽  
Author(s):  
Maha. Ali. Abusogi
Keyword(s):  
Numerical Analysis ◽  
Drying Shrinkage ◽  
Early Age ◽  
Edge Distance

Influence of Early Age Volume Changes on Long-Term Concrete Shrinkage

1998 ◽  
Vol 1610 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Erika E. Holt ◽  
Donald J. Janssen
Keyword(s):  
Concrete Slab ◽  
Drying Shrinkage ◽  
Early Age ◽  
Volume Changes ◽  
Test Procedures ◽  
Cracking Behavior ◽  
Concrete Shrinkage ◽  
Cracking Potential ◽  
Partially Restrained

Volume changes can occur in concrete during the first 24 hr and are generally missed in laboratory shrinkage evaluations. Unfortunately these early age volume changes are present in real pavements and structures and can contribute to the cracking behavior of the concrete at later ages. Early age volume changes can occur in two forms: drying shrinkage before the start of curing and autogenous volume changes. Although these early age volume changes are often dismissed as being insignificant, recent work in Europe has identified magnitudes for early age volume changes of some concretes that are equal to or greater than 28-day drying shrinkage measurements. Expansions have also been identified in some cases. The results of some investigations of volume changes in concrete during the first 24 hr under both drying and nondrying conditions are presented. An example of potential long-term cracking under partially restrained conditions (concrete slab-on-grade modeled by a concrete ring cast around a hollow steel ring) is used to illustrate the magnitude of influence of early age volume changes on concrete cracking. Both test procedures employ nonstandard methods to quantify the cracking potential of concrete.

Parameter Analysis of the Reinforcement for the Width and Spacing Control of the Early-Age Cracks in Concrete

2016 ◽  
Vol 691 ◽  
pp. 14-27
Author(s):  
Robert Sonnenschein ◽  
Juraj Bilčík ◽  
Katarína Gajdošová
Keyword(s):  
Drying Shrinkage ◽  
Peak Level ◽  
Parameter Analysis ◽  
Early Age ◽  
Reinforcing Bars ◽  
Volume Changes ◽  
Concrete Element ◽  
Thermal Movement ◽  
Cover Thickness ◽  
Crack Widths

Early-age volume changes in concrete induced by temperature change, hydration, autogenous and drying shrinkage can lead to concrete cracking and this can have lasting effects on serviceability, durability or aesthetics of the structure. The restraint to thermal movement is the product of the coefficient of the temperature fall from a peak level during cement hydration and a restraint factor. In most cases it is not necessary and also not economical to avoid cracks. In these cases, crack widths are limited due to water tightness, durability or aesthetic reasons. If early-age thermal cracking cannot be prevented, crack width can be controlled with reinforcement. The reinforcement distributes cracks and consequently reduces their widths and spacing. As a result, there forms a large number of smaller cracks instead of a few through-cracks. This means, that due to the formation of fine cracks, the strain capacity of a reinforced concrete element before the occurrence of through cracks can be increased with the help of skin reinforcement. This paper discusses the parameters of reinforcement affecting the width and spacing of early-age cracks in concrete. The effect of reinforcement on early-age cracking in concrete was investigated on numerical simulation and in full-scale experiments. The test variables were the reinforcement ratio and the cover thickness of the longitudinal reinforcing bars.

The Early-Age Drying Shrinkage of Cement-Based Materials with the same Workability after Temperature Compensation

2013 ◽  
Vol 405-408 ◽  
pp. 2604-2609
Author(s):  
Li Feng Zhang ◽  
Jun Ying Lai ◽  
Xiao Qian Qian ◽  
Chong Shen
Keyword(s):  
Temperature Compensation ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Concrete Specimen ◽  
Temperature Deformation ◽  
Control Group ◽  
Early Age ◽  
Peak Time ◽  
Initial Setting Time ◽  
Cement Based Materials

The early age drying shrinkage of cement-based materials with same the same workability staring from the initial setting time was studied. Superplasticizers (SP) were used to get the same workability. The drying shrinkage of paste was measured by clock gauge, and CABR-NES deformation instrument was used to measure the shrinkage of concrete. Temperature probes were buried into both paste and concrete specimen cores to measure the temperature curve, and temperature deformation was considered into the early shrinkage. Results show the addition of SP increases much more shrinkage than the control group, and polycarboxylate SP increases more shrinkage than naphthalene SP. The different temperature peak time of different mixtures show that the addition of SP changes the hydration process of cement, and the shrinkage of cement-based materials after temperature compensation is bigger than the measured value in the first 6 hours, but the gap is not big.

scholarly journals Performance of Fly Ash-Based Inorganic Polymer Mortar with Petroleum Sludge Ash

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4143
Author(s):  
Mubarak Usman Kankia ◽  
Lavania Baloo ◽  
Nasiru Danlami ◽  
Bashar S. Mohammed ◽  
Sani Haruna ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Sodium Hydroxide ◽  
Waste Product ◽  
Drying Shrinkage ◽  
Weight Percent ◽  
Early Age ◽  
Petroleum Sludge ◽  
Precursor Material ◽  
Polymer Mortar ◽  
Sludge Ash

Petroleum sludge is a waste product resulting from petroleum industries and it is a major source of environmental pollution. Therefore, developing strategies aimed at reducing its environmental impact and enhance cleaner production are crucial for environmental mortar. Response surface methodology (RSM) was used in designing the experimental work. The variables considered were the amount of petroleum sludge ash (PSA) in weight percent and the ratio of sodium silicate to sodium hydroxide, while the concentration of sodium hydroxide was kept constant in the production of geopolymer mortar cured at a temperature of 60 °C for 20 h. The effects of PSA on density, compressive strength, flexural strength, water absorption, drying shrinkage, morphology, and pore size distribution were investigated. The addition of PSA in the mortar enhanced the mechanical properties significantly at an early age and 28 days of curing. Thus, PSA could be used as a precursor material in the production of geopolymer mortar for green construction sustainability. This study aimed to investigate the influence of PSA in geopolymer mortar.

Computational Modeling of Drying Shrinkage in Early‐Age Concrete

PAMM ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Mehran Ghasabeh ◽  
Serdar Göktepe
Keyword(s):  
Computational Modeling ◽  
Drying Shrinkage ◽  
Early Age ◽  
Early Age Concrete
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