scholarly journals Bioconcrete Development Using Calcite -Precipitating Bacteria Isolated From Different Sources in Jordan

2019 ◽  
Vol 278 ◽  
pp. 01011
Author(s):  
Suha M. Abudoleh ◽  
Amal Al Mahayreh ◽  
Aya Al Frejat ◽  
Fatima Al Hulaisy ◽  
Sara O. Hamdan
Keyword(s):  
Cement Mortar ◽  
Construction Material ◽  
Negative Control ◽  
Self Healing ◽  
Test Results ◽  
Promising Technique ◽  
Sealing Material ◽  
Fava Beans ◽  
Harsh Conditions ◽  
Different Sources

Concrete is considered as the most widely used construction material in the world. However, concrete is exposed to cracks due to different factors like overloads, temperature, shrinkage, earthquakes and others. These cracks reduce the strength, the service life of the structure, and increase the permeability of the concrete. Thus, the importance of "self-healing concrete" is highlighted nowadays, with emphasis on a special type of concrete called bioconcrete, which is a concrete that has the ability to self-heal the microcracks that happen due to overloads. This ability comes from the bacteria used in the concrete mix which have special characteristics such as the ability to live in harsh conditions similar to those found in the concrete environment, in addition to their ability to precipitate calcite (calcium carbonate (CaCO3)), the sealing material in the cracks. This study aims to assess the performance of self-healing Bacillus mycoides incorporated into Portland cement mortar. This bacterium has been isolated from the soil of Fava beans in Jordan. Cracking of specimens was induced by load percent concept after 7 days of curing and tests were performed at 21 days of cracking. The testing scheme for the mortar included bacterial sporulation tests inside mortar specimens, acid fizz test and a compression test. Results demonstrated that self-healing bacteria is a promising technique in minimizing cracking. The rate of healing using bacteria was higher than the bacteria-free negative control.

scholarly journals Transformation of Construction Cement to a Self-Healing Hybrid Binder

2019 ◽  
Vol 20 (12) ◽  
pp. 2948 ◽  
Author(s):  
Werner E.G. Müller ◽  
Emad Tolba ◽  
Shunfeng Wang ◽  
Qiang Li ◽  
Meik Neufurth ◽  
...  
Keyword(s):  
Soil Bacteria ◽  
Construction Material ◽  
Water Soluble ◽  
The Self ◽  
Average Chain Length ◽  
Self Healing ◽  
Cement Concrete ◽  
Low Concentrations ◽  
Natural Mechanism ◽  
Long Chain

A new biomimetic strategy to im prove the self-healing properties of Portland cement is presented that is based on the application of the biogenic inorganic polymer polyphosphate (polyP), which is used as a cement admixture. The data show that synthetic linear polyp, with an average chain length of 40, as well as natural long-chain polyP isolated from soil bacteria, has the ability to support self-healing of this construction material. Furthermore, polyP, used as a water-soluble Na-salt, is subject to Na+/Ca2+ exchange by the Ca2+ from the cement, resulting in the formation of a water-rich coacervate when added to the cement surface, especially to the surface of bacteria-containing cement/concrete samples. The addition of polyP in low concentrations (<1% on weight basis for the solids) not only accelerated the hardening of cement/concrete but also the healing of microcracks present in the material. The results suggest that long-chain polyP is a promising additive that increases the self-healing capacity of cement by mimicking a bacteria-mediated natural mechanism.

Physical Properties of Cement Mortar Containing Waste Ash

2015 ◽  
Vol 804 ◽  
pp. 129-132
Author(s):  
Sumrerng Rukzon ◽  
Prinya Chindaprasirt
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Cement Mortar ◽  
Ash Content ◽  
Water Requirement ◽  
Test Results ◽  
Pozzolanic Material ◽  
Materials Used

This research studies the potential for using waste ash from industrial and agricultural by-products as a pozzolanic material. Classified fly ash (FA) and ground rice husk ash (RA) were the materials used. Water requirement, compressive strength and porosity of cement mortar were investigated. Test results indicated that FA and RA (waste ash) have a high potential to be used as a good pozzolanic material. The water requirement of mortar mix decreases with the increases in fly ash content. For ground rice husk ash (RA), the water requirement of mortar mix increases with the increases in rice husk ash content. In addition, the reduction in porosity was associated with the increase in compressive strength.

Development of Nanocement Mortar as a Construction Material

2013 ◽  
Vol 795 ◽  
pp. 684-691 ◽  
Author(s):  
Wail N. Al-Rifaie ◽  
Omar Mohanad Mahdi ◽  
Waleed Khalil Ahmed
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Cement Mortar ◽  
Construction Material ◽  
Modulus Of Rupture ◽  
Early Stages

The present research examined the compressive and flexural strength of nanocement mortar by using micro cement, micro sand, nanosilica and nanoclay in developing a nanocement mortar which can lead to improvements in ferrocement construction. The measured results demonstrate the increase in compressive and flexural strength of mortars at early stages of hardening. In addition, the influence of heating on compressive strength of cement mortar. General expressions to predict the compressive strength, modulus of rupture for the developed nanocement mortar in the present work are proposed.

Watertightness, cracking resistance, and self-healing of asphalt concrete used as a water barrier in dams

2013 ◽  
Vol 50 (3) ◽  
pp. 275-287 ◽  
Author(s):  
Yingbo Zhang ◽  
Kaare Höeg ◽  
Weibiao Wang ◽  
Yue Zhu
Keyword(s):  
Asphalt Concrete ◽  
Leakage Rate ◽  
Strain Rates ◽  
Self Healing ◽  
Test Results ◽  
Direct Tension ◽  
Coefficient Of Permeability ◽  
Tension Tests ◽  
Laboratory Test Results ◽  
Cracked Specimens

The coefficient of permeability of hydraulic asphalt concrete is in the range 10−8–10−10 cm/s. Laboratory test results show that triaxial specimens in axial compression can undergo axial strains up to 18% without any significant increase in permeability until approaching the compressive strength. For temperatures between 5 and 20 °C and strain rates between 2 × 10−3%/s and 5 × 10−3%/s, conventional hydraulic asphalt concrete can tolerate 1%–3% tensile strains before cracking in direct tension tests and strains up to 3%–4% in bending. At 20 °C the tensile and bending strains at cracking are 2–4 times higher than those at 0 °C, and at −20 °C they are approximately 0.2% and 0.8%, respectively. Asphalt concrete possesses pronounced crack self-healing properties. In the experiments, the crack leakage rate dropped 1–4 orders of magnitude within a few hours and the cracked specimens regained 55% of the intact tensile strength after only 1 day of self-healing. In summary, the comprehensive series of laboratory tests documents that asphalt concrete has characteristics that make the material extremely well suited for use in impervious barriers in dams, and the test results reported herein can be of great use in barrier design.

EFFECT OF YELLOW LOESS ON ODOROUS GAS ADSORPTION AND ECOTOXICITY TEST USING DAPHNIA MAGNA

2021 ◽  
Vol 16 (1) ◽  
pp. 103-114
Author(s):  
Hongseok Jang ◽  
Boram Lee ◽  
Seungyoung So
Keyword(s):  
Daphnia Magna ◽  
Cement Mortar ◽  
Construction Material ◽  
Objective Assessment ◽  
Test Chamber ◽  
Construction Materials ◽  
Ecotoxicity Test ◽  
Lamellar Crystal ◽  
Exposure Test ◽  
Natural Materials

ABSTRACT To minimize damage caused by harmful substances released from artificial construction materials, there has been increasing interest in eco-friendly houses constructed with natural materials. Among natural materials, yellow loess is South Korea’s most representative eco-friendly construction material, with high purification performance for indoor use. However, there has been no objective assessment of yellow loess’s performance at purifying indoor air. In this study, internal pores were found in yellow loess that were of a lamellar crystal structure consisting of bonds of silica and alumina plates, and there was a high negative charge on the loess surface; these might have contributed to the excellent performance of yellow loess in adsorbing odorous gas. There was also an exposure test using Daphnia magna to determine the eco-friendliness of yellow loess compared with that of cement mortar. Results showed the survival of Daphnia magna was longer in the indoor environment of a test chamber with higher concentration of ammonia wherein yellow loess was placed. EC50 (median effective concentration, the concentration that caused death of 50% of bio-specimens) value of 19 ml of ammonia (0.1% solution), which was three times more than EC50 value of 6 ml of ammonia of the same area of cement mortar.

scholarly journals Effect of ultrafine natural steatite powder, super plasticizer and VMA on the fresh and hardened properties of self-compacting cement paste and mortar

2021 ◽  
Author(s):  
S. Christopher Gnanaraj ◽  
Ramesh Babu Chokkalingam ◽  
G. Lizia Thankam ◽  
S.K.M. Pothinathan
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Water Demand ◽  
Construction Material ◽  
Setting Time ◽  
Mineral Admixture ◽  
Self Healing ◽  
Chemical Admixtures ◽  
Hardened Properties ◽  
Viscosity Modifying Admixture

AbstractFor the past few decades innovation in construction material has grown a lot. This leads to special concrete such as self-compacting concrete, geopolymer concrete, self-healing concrete, etc. To prepare a special concrete apart from regular concreting material some sort of special materials was also needed, like mineral and chemical admixtures. Hence it is necessary to study the effect of these admixtures in cement paste and mortar before studying the same in concrete. Hence an attempt is made to study the effect of mineral and chemical admixtures in the fresh and hardened properties of cement paste and mortar. For this study ultrafine natural steatite powder is taken as mineral admixture and polycarboxylic based superplasticizer and glenium stream 2 were taken as chemical admixtures. Ultrafine natural steatite powder was used as additive to cement in various percentages like 0%, 5%, 10%, 15%, 20% and 25%. Superplasticizer and viscosity modifying admixture were taken as 1.5% and 0.5%, respectively. Then various combinations were worked out. To study the fresh property of cement paste consistency, initial setting time and miniature slump cone test were done based on the results yield stress of cement paste also calculated empirically. To study the hardened property compression test on cement mortar was done. Based on the test results it is clear that the addition of ultrafine natural steatite powder increases the water demand hence reduces the workability. On the other hand, it increases the compressive strength up to a certain limit. Adding superplasticizer increases the workability and reduces the water demand and viscosity modifying admixture reduces the bleeding and segregation effects hence increases the compressive strength.

scholarly journals Effects of microbial agents to the properties of fly ash-based paste

2018 ◽  
Vol 195 ◽  
pp. 01012
Author(s):  
Kiki Dwi Wulandari ◽  
Januarti Jaya Ekaputri ◽  
Triwulan ◽  
Chikako Fujiyama ◽  
Davin H. E. Setiamarga
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Cement Paste ◽  
Construction Material ◽  
Concrete Strength ◽  
Self Healing ◽  
Concrete Mixtures ◽  
Microbial Agents ◽  
Portland Cement Paste ◽  
Geopolymer Paste

Specific microbial agents such as bacteria are often used in concrete to improve its performance. Some microbes act as self-healing agents to close cracks in concrete, and to increase concrete strength. This paper presents a study to observe the effects of microbe addition to two types of concrete mixtures the fly ash-based, as geopolymer paste, and portland cement paste containing fly ash. Furthermore, the investigation was conducted to compare the properties of each paste, such as its compressive strengths, specific gravities, porosity, microstructures, and XRay diffracting properties. The results indicate that microbial activities positively affected the properties of both, portland cement paste and geopolymer paste. The result reported here strongly suggests that fly ash can be used to produce a high quality, but environmental friendly construction material when it’s mixed together with useful microbes.

Treating Lead-Contaminated Soil by Stabilization and Solidification

1998 ◽  
Vol 1615 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Richard P. Long ◽  
Xinguo Zhang
Keyword(s):  
Contaminated Soil ◽  
Standard Test ◽  
Dry Density ◽  
Test Results ◽  
Promising Technique ◽  
Diffusion Test ◽  
The Public ◽  
Toxic Materials ◽  
Direct Exposure ◽  
Dynamic Diffusion

Soil in and near transportation facilities often is contaminated with lead because lead once was used as a base for gasoline and paint. Dealing with contaminated soil is difficult because the toxic material must be treated to protect the public from direct exposure. Stabilization and solidification is a promising technique for protecting the public from toxic materials in soils by decreasing the possibility of human exposure and decreasing the mobility of the contaminant. The results of a laboratory investigation of the feasibility of stabilization and solidification of contaminated soil using cement in combination with various additives are presented. Mobility of lead and other contaminants was measured by dynamic diffusion and compared with the standard test results of the toxic characteristic leaching procedure. Several additives were tried. Apatite and sodium silicate were found to be the most effective in reducing the mobility of the lead. The compacted dry density of the solidified soil had a great effect on the leaching characteristics. The leaching of lead from deteriorated solidified soil was simulated by crushing a sample containing apatite and conducting a dynamic diffusion test on the crushed sample. The diffusion coefficient was used to compare the effect of additives and other treatments.

scholarly journals Geotechnical Properties of Anthropogenic Soils in Road Engineering

2020 ◽  
Vol 12 (12) ◽  
pp. 4843
Author(s):  
Andrzej Głuchowski ◽  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Raimondas Šadzevičius ◽  
Wojciech Sas
Keyword(s):  
Cyclic Loading ◽  
Bearing Capacity ◽  
Construction Material ◽  
Bottom Ash ◽  
Field Tests ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Test Results ◽  
Anthropogenic Soils ◽  
Road Engineering

The construction of a roads network consumes high amounts of materials. The road materials are required to fulfill high standards like bearing capacity and low settlement susceptibility due to cyclic loading. Therefore, crushed aggregates are the primary subbase construction material. The material-intensity of road engineering leads to depletion of natural resources, and to avoid it, the alternative recycled materials are required to be applied to achieve sustainable development. The anthropogenic soils (AS), which are defined as man-made unbound aggregates, are the response to these requirements. For the successful application of the AS, a series of geotechnical laboratory and field tests were conducted. In this article, we present the set of 58 test results, including California Bearing Ratio (CBR) bearing capacity tests, oedometric tests, and cyclic CBR tests, to characterize the behavior of three AS types and to compare its reaction with natural aggregate (NA). The AS tested in this study are recycled concrete aggregate (RCA), fly ash and bottom ash mix (BS), and blast furnace slag (BFS). The results of the tests show that the AS has similar characteristics to NA, and in some cases, like compression characteristic, RCA and BFS behave a stiffer response to cyclic loading. The test results and analysis presented here extend the knowledge about AS compressibility and AS response to cyclic loading.

Development and Characterization of Squalene-Loaded Topical Agar-Based Emulgel Scaffold: Wound Healing Potential in Full-Thickness Burn Model

2020 ◽  
pp. 153473462092162
Author(s):  
T. S. Shanmugarajan ◽  
N. Kalai Selvan ◽  
Varuna Naga Venkata Arjun Uppuluri
Keyword(s):  
Wound Healing ◽  
Tissue Regeneration ◽  
Macrophage Polarization ◽  
Negative Control ◽  
Skin Tissue ◽  
Self Healing ◽  
Full Thickness ◽  
Burn Wound ◽  
Burn Wound Healing ◽  
Tissue Defects

Full-thickness burns pose a major challenge for clinicians to handle because of their restricted self-healing ability. Even though several approaches have been implemented for repairing these burnt skin tissue defects, all of them had unsatisfactory outcomes. Moreover, during recent years, skin tissue engineering techniques have emerged as a promising approach to improve skin tissue regeneration and overcome the shortcomings of the traditional approaches. Although previous literatures report the wound healing effects of the squalene oil, in the current study, for the first time, we developed a squalene-loaded emulgel-based scaffold as a novel approach for potential skin regeneration. This squalene-loaded agar-based emulgel scaffold was fabricated by using physical cross-linking technique using lecithin as an emulsifier. Characterization studies such as X-ray diffraction, Fourier-transform infrared spectroscopy, and field emission scanning electron microscopy revealed the amorphous nature, chemical interactions, and cross-linked capabilities of the developed emulgel scaffold. The squalene-loaded emulgel scaffold showed excellent wound contraction when compared with the agar gel and negative control. In case of the histopathology and recent immunohistochemistry findings, it was clearly evidenced that squalene-loaded emulgel promoted faster rate of the revascularization and macrophage polarization in order to enhance the burn wound healing. Moreover, the findings also revealed that the incorporation of squalene oil into the formulation enhances collagen deposition and accelerates the burnt skin tissue regeneration process. Finally, we conclude that the squalene-loaded emulgel scaffold could be an effective formulation used in the treatment of the burnt skin tissue defects.

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