scholarly journals Durability of Structural Lightweight Concrete with Sintered Fly Ash Aggregate

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4565 ◽  
Author(s):  
Lucyna Domagała
Keyword(s):  
Fly Ash ◽  
Moisture Content ◽  
Water Absorption ◽  
Water Permeability ◽  
Lightweight Concrete ◽  
Concrete Strength ◽  
Initial Moisture Content ◽  
Cement Matrix ◽  
Secondary Importance ◽  
Freeze Thaw

The aim of this study was to present the problem of durability of structural lightweight concrete made of a sintered fly ash aggregate. The issue of durability was researched for 12 concrete series in terms of their water absorption, water permeability, and freeze-thaw resistance. Additionally, the microstructure of several concretes was analyzed with a scanning electron microscope (SEM). In the durability research, the influences of the following parameters were taken into consideration: The initial moisture content of sintered fly ash (mc = 0, 17–18, and 24–25%); the aggregate grading (4/8 and 6/12 mm); and the water-cement ratio (w/c = 0.55 and 0.37). As a result of various compositions, the concretes revealed different properties. The density ranged from 1470 to 1920 kg/m3, and the corresponding strength ranged from 25.0 to 83.5 MPa. The durability research results of tested lightweight concretes showed that, despite considerably higher water absorption, a comparable water permeability and comparable or better freeze-thaw resistance in relation to normal-weight concrete may be present. Nevertheless, the fundamental requirement of lightweight concrete to achieve good durability requires the aggregate’s initial moisture content to be limited and a sufficiently tight cement matrix to be selected. The volume share of the cement matrix and aggregate, the cement content, and even the concrete strength are of secondary importance.

scholarly journals The Synergy between Bio-Aggregates and Industrial Waste in a Sustainable Cement Based Composite

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6158
Author(s):  
Cătălina Mihaela Grădinaru ◽  
Adrian Alexandru Șerbănoiu ◽  
Radu Muntean ◽  
Bogdan Vasile Șerbănoiu
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Splitting Tensile Strength ◽  
Partial Replacement ◽  
Cement Matrix ◽  
Freeze Thaw ◽  
Corn Cobs ◽  
Study Results ◽  
Sunflower Stalks

The effects of the fly ash and of the sunflower stalks and corn cobs within a cement-matrix composite were studied under the aspects of density, compressive strength, splitting tensile strength, elasticity modulus, and resistance to repeated freeze-thaw cycles. In the research were developed 20 recipes of cement-based composite, including the reference composite. Fly ash was used as partial cement replacement (10, 20 and 30% by volume), and the vegetal aggregates made by corn cobs and sunflower stalks as partial replacement of the mineral aggregates (25 and 50% by volume). The study results revealed that a lightweight composite can be obtained with 50% of vegetal aggregates, and the fly ash, no matter its percentage, enhanced the compressive strength and splitting tensile strength of the compositions with 50% of sunflower aggregates and the freeze-thaw resistance of all compositions with sunflower stalks.

scholarly journals Influence of Freeze-Thaw Cycles on Mechanical Response of Levee Pavement

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shuan Guo ◽  
Zheng Lu ◽  
Guokun Liu ◽  
Baoli Zhuang ◽  
Yongfeng Fan ◽  
...  
Keyword(s):  
Moisture Content ◽  
Mechanical Response ◽  
Triaxial Compression ◽  
Initial Moisture Content ◽  
Dry Density ◽  
Test Results ◽  
Freeze Thaw ◽  
Temperature Range ◽  
Pavement Structure ◽  
The Stability

The freeze-thaw cycles cause deterioration in mechanical properties of levee soil and further endanger the pavement structure on the embankment. This study attempts to comprehensively understand the mechanical response of pavement after freeze-thaw cycles. In this paper, the freeze-thaw cycles test under an open system was carried out, and then the triaxial compression test was conducted. Based on the test results, the effects of freeze-thaw cycles, temperature range, initial dry density, and initial moisture content of embankment soil on the mechanical response of road structure after freeze-thaw were calculated and analyzed. Finally, the stability of the slope of the levee was evaluated. The results show that the number of freeze-thaw cycles has the most significant impact on the mechanical response of pavement, the stress and strain of the structural layers vary in different ranges, and the pavement deflection increases by 5 times after 7 freeze-thaw cycles. However, the initial dry density and initial moisture content of the soil have little influence on the pavement structure, and the temperature range will exert an influence when it exceeds a certain threshold.

scholarly journals Olive pomace based lightweight concrete, an experimental approach and contribution

2018 ◽  
Vol 149 ◽  
pp. 01068
Author(s):  
Chaabane Lynda Amel ◽  
Benferrah Rafik
Keyword(s):  
Mechanical Strength ◽  
Experimental Approach ◽  
Lightweight Concrete ◽  
Concrete Strength ◽  
Lightweight Aggregate ◽  
Cement Matrix ◽  
Lightweight Aggregate Concrete ◽  
High Porosity ◽  
Olive Pomace ◽  
Statistical Survey

Due to conventional aggregates resources depletion, material recycling has become an economic and ecologic alternative. In this paper, locally available natural residues such as olive pomace were investigated, when partially incorporated in the concrete formulation, since the mechanical characteristics of lightweight aggregate concrete strongly depend on its properties and proportions. Lightweight aggregates are more deformable than the cement matrix because of their high porosity, and their influence on the concrete strength remains complex. The purpose of this paper is to investigate the aggregates properties on lightweight concrete mechanical behaviour through an experimental approach. In addition, the different substitution sequences and the W/C ratio on lightweight concrete behaviour were evaluated, in order to determine the W/C ratio influence on the improvement of the lightweight concrete mechanical properties while knowing that the mixing water quantity gives the cement paste manoeuvrability and mechanical strength effects. The last part of this paper, therefore, was to provide statistical survey for estimating strength and weight reduction through the different natural aggregate substitutions to improve the lightweight concrete properties. The results achieved in a significant olive-pomace lower adhesion with the matrix after the cement setting, making the lightweight concrete mechanical strength weak. However, this work can open several perspectives: Results modeling and correlation with an experimental approach, the evolution and determination of lightweight concrete characteristics when exposed to high temperatures and thermohydric properties.

DURABILITY PERFORMANCE OF OIL PALM SHELL LIGHTWEIGHT CONCRETE FOR INSULATION BUILDING MATERIAL

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
Eravan Serri ◽  
Mohd Zailan Suleiman ◽  
Roslan Talib ◽  
Mahyuddin Ramli
Keyword(s):  
Thermal Conductivity ◽  
Water Absorption ◽  
Oil Palm ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
Cement Matrix ◽  
Void Content ◽  
Palm Shell ◽  
Oil Palm Shell ◽  
Durability Performance

The advantage of oil palm shell (OPS) as coarse aggregate in concrete can be extended to insulation concrete capacity. Thus, this paper will explain the durability of oil palm shell lightweight concrete (OPSLC) for insulation concrete capacity in building. Nine mix designs were developed containing high volume of OPS, which is 30, 32 and 34% from total volume of concrete with three different OPS shapes (raw, crushed and partly crushed). The water absorption and drying shrinkage were examined; besides, thermal conductivity testing that was conducted for confirmation as insulation concrete category.  The observation of all the specimens lasted one year for durability performance test and 28 days for thermal conductivity value. The highest water absorption value is 43% from previous study that was designed for structural concrete. Higher OPS volume fraction produced higher air void content and caused water loss and increase of the hydration effects on OPSLC shrinkage. It also affected the microstructure conditions, especially specimens that used 34% of OPS volume fraction which show weak interface bond in cement matrix.

scholarly journals Ilmenite Mud Waste as an Additive for Frost Resistance in Sustainable Concrete

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2904 ◽  
Author(s):  
Filip Chyliński ◽  
Krzysztof Kuczyński
Keyword(s):  
Titanium Dioxide ◽  
Fly Ash ◽  
Frost Resistance ◽  
Building Materials ◽  
Industrial Wastes ◽  
Cement Matrix ◽  
Freeze Thaw ◽  
Sustainable Concrete ◽  
Potential Risks ◽  
Air Void

Sustainable development leads to the production of building materials that are safer for the environment. One of the ways to achieve sustainability in materials is the addition of industrial wastes and by-products, especially to concrete. However, the addition of waste to concrete often decreases its durability and the scope of aggression of the environment in which the concrete is used has to be reduced. Making sustainable concrete, which is also durable in more aggressive environments, is rather difficult. This article presents the results of tests performed on concrete containing ilmenite mud waste from the production of titanium dioxide, which was exposed to frost aggression with and without de-icing salts. The results have shown that a sustainable and frost resistant concrete can be made. After 200 freeze–thaw cycles, the compressive strength of the tested concretes decreased by less than 4%. Concretes were highly resistant for scaling and after 112 freeze–thaw cycles in water with de-icing salt, the scaled mass was less than 0.02 kg/m2. The air void distribution has also been analyzed. The results suited the requirements for frost resistance concrete and were similar to those obtained for a reference concrete with fly ash. The examination of the microstructure using scanning electron microscopy (SEM) has not shown any potential risks that might affect the durability of concrete. Particles of waste were thoroughly combined in the binder and some of its constituents seem to be an active part of the cement matrix. Long-term tests of shrinkage (360 days) have not shown any excessive values that would differ from the reference concrete with fly ash. The presented results have shown that sustainable concrete containing ilmenite mud waste from the production of titanium dioxide might also be resistant to frost aggression.

Effects of cyclic freezing and thawing on volume changes and permeabilities of soft fine-gained soils

1996 ◽  
Vol 33 (4) ◽  
pp. 529-537 ◽  
Author(s):  
K D Eigenbrod
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Maximum Volume ◽  
Freezing And Thawing ◽  
Volume Changes ◽  
One Dimensional ◽  
Freeze Thaw ◽  
Fine Grained ◽  
Liquidity Index ◽  
Thaw Consolidation

Soft, fine-grained soils were exposed to cyclic one-dimensional, open-system freezing and thawing, resulting in maximum volume changes of up to 30%, depending on the initial moisture content and plasticity of the clay as well as on the rate of freezing. A linear relationship between the net volume changes subsequent to freezing and thawing and the liquidity index prior to freezing and thawing was obtained. This correlation is not unique, but depends on rate and mode of freezing. Thus, settlements from freeze–thaw consolidation in the field can be predicted from such tests if the rate and mode of freezing are the same as in the field. During cyclic freezing and thawing the soils became fissured and jointed, resulting for most clays in large increases in their bulk permeabilities, which increased with an increasing number of freeze–thaw cycles, often by more than two orders of magnitude. For some materials, however, little change in permeability occured. Key words: cyclic freeze–thaw, clays, freeze–thaw consolidation, permeability, volume changes.

scholarly journals Results of the correlation analysis of experimental data about initial moisture content and water absorption of the foam-polymer-mineral insulation of an underground heat steel pipe

2018 ◽  
Vol 3 ◽  
pp. 11-16
Author(s):  
Belyj V.S. ◽  
Bryl S.V.
Keyword(s):  
Experimental Data ◽  
Correlation Analysis ◽  
Moisture Content ◽  
Water Absorption ◽  
Initial Moisture Content ◽  
Random Variable ◽  
Final Moisture Content ◽  
Steel Pipe ◽  
Statistical Hypothesis ◽  
Correlation Dependence

In this article the technique of a research of correlation dependence between initial and final moisture content of the foam-polymer-mineral (PPM) insulation of an underground heat steel pipe and also results of check of a statistical hypothesis of a type of distribution of a random variable of water absorption of PPM isolation is offered. The nature of distribution established as a result of a research speaks about existence of a limit of opportunities of PPM isolation of a pipe for water absorption – isolation with low initial moisture content is capable to absorb in itself more moisture and vice versa. Absorption of moisture happens until the value of final moisture content of PPM isolation does not reach extremely possible value approximately identical on all volume of isolation.

scholarly journals The transport properties of cement mortars subjected to freeze-thaw cycles

2018 ◽  
Vol 49 ◽  
pp. 00128
Author(s):  
Alicja Wieczorek ◽  
Marcin Koniorczyk ◽  
Dalia Bednarska ◽  
Kalina Grabowska
Keyword(s):  
Absorption Coefficient ◽  
Water Absorption ◽  
Transport Properties ◽  
Positive Impact ◽  
Gas Permeability ◽  
Cement Matrix ◽  
Capillary Absorption ◽  
Water Absorption Coefficient ◽  
Freeze Thaw ◽  
Cement Mortars

The parameters characterizing the microstructure of cementbased materials, such as porosity or permeability, determine not only durability, but also risk of degradation of the cement matrix due to an aggressive environment. The report presents results of a research on transport properties of cement mortars subjected to cyclic water freezing. Mortars prepared on the basis of two different cements were the object of the research: Portland cement CEM I 42.5R and Portland blast-furnace slag cement CEM III/A 42.5N LH/HSR/NA, with two water-cement ratio (w/c=0.45 and 0.40). The experimental study was carried out in order to determine the relationship between intrinsic permeability and the water absorption coefficient in relation to the number of freeze-thaw cycles. The evolution of transport coefficients was determined using a capillary absorption test and the modified RILEM-Cembureau method. It was established that the degradation processes induced an increase of transport properties. Moreover, the microcracks had a more significant influence on permeability and lesser influence on the water absorption coefficient. The gas permeability of damaged mortar changed very significantly, an increase with several orders of magnitude could be noticed. Moreover, the positive impact of CEM III on ice-induced degradation was also visible.

Mechanical Characteristics of Concrete Exposed to External Flexural Load, De-Icing Salt and Freeze-Thaw Cycles

2011 ◽  
Vol 250-253 ◽  
pp. 33-39
Author(s):  
Xiao Lu Yuan ◽  
Bei Xing Li ◽  
Shang Chuan Zhao ◽  
Shi Hua Zhou
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Ordinary Portland Cement ◽  
Mechanical Characteristics ◽  
Concrete Strength ◽  
Mineral Admixtures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Freeze Thaw

This paper investigates mechanical characteristics of concrete exposed to external flexural load, de-icing salt and freeze-thaw cycles. Concrete specimens made with ordinary Portland cement or ordinary Portland cement incorporating fly ash with the replacement of 10% or 20%, or 0.7/10000 air-entraining agent and 20% fly ash, or ground blast furnace slag with the replacement of 15% or 30%, were made and exposed to flexural load, freeze-thaw and de-icing salt environment. Mechanical properties of concrete including compressive strength and flexural strength were measured. Phase composition of samples was determined by means of x-ray diffraction (XRD). Results indicate that increasing flexural stress ratios reduced compressive strength and flexural strength of concrete, and presented higher improvement of mineral admixtures in concrete strength. Incorporation of mineral admixtures and air-entraining agent decreased the loss of concrete strength. X-ray diffraction analysis showed the presence of abundant calcium chloroaluminate and ettringite in paste samples.

scholarly journals The mechanical properties and thermal conductivity of bamboo with freeze–thaw treatment

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Jieyu Wu ◽  
Xianke Wang ◽  
Benhua Fei ◽  
Xiang Xu ◽  
Caiping Lian ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Chemical Composition ◽  
Moisture Content ◽  
Bending Strength ◽  
Testing Machine ◽  
Initial Moisture Content ◽  
Crystallinity Index ◽  
Phyllostachys Pubescens ◽  
Freeze Thaw

AbstractThe aim of this research was to investigate the effect of freeze–thaw treatment on bamboo with different initial moisture content (water-saturated, air-dried and oven-dried). Bamboo (Phyllostachys pubescens) were treated with two freeze treatments and its microstructure, chemical composition, mechanical properties and thermal conductivity were characterized by field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), mechanical testing machine and thermal conductivity tester, respectively. The results showed that the freeze–thaw treatment had little influence on the microstructure of bamboo, the chemical composition content and the cellulose crystalline structure of bamboo were also not altered. The crystallinity index was found to increase with the increase of initial moisture content. The bending strength and elastic modulus of the treated bamboo increased, the extent of the increase was dependent on the initial moisture content and the freezing temperature. The thermal conductivity of the treated bamboo increased remarkably, which might be possibly determined by the cellulose crystallinity, moisture content, and density of bamboo.

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