Microbial Carbonate Mineralization as an Improvement Method for Durability of Concrete Structures

2011 ◽  
Vol 365 ◽  
pp. 280-286 ◽  
Author(s):  
Pei Hao Li ◽  
Wen Jun Qu
Keyword(s):  
Laboratory Experiments ◽  
Concrete Structures ◽  
Capillary Water ◽  
Water Penetration ◽  
Mineral Crystal ◽  
Microbial Carbonate ◽  
Improvement Method ◽  
Alternative Techniques ◽  
Capillary Water Uptake ◽  
Durability Of Concrete

Biodeposition treatment had been proposed as alternative techniques for improvement in the durability of concrete structures. Laboratory experiments were conducted by bacterially mediated carbonate precipitation on the surface and subsurface of specimens of concrete. Some properties of specimens and crystal, such as the crystal phase, morphology and growth of the crystal deposited on specimens, water penetration, the resistance towards carbonation of concrete and so on, were analyzed by XRD, SEM, water absorptivity test and concrete accelerated carbonation test. Some efficiencies of biodeposition treatment for were investigated by experiment. Results show that the mineral crystal deposits uniformly on the surface and subsurface of specimens, phases of crystal are calcite and vaterite. Biodeposition effectively reduces capillary water uptake and leading to carbonation rate constant decreased by 25~40%. Bacterially mediated carbonate mineralization can be an ecological and novel alternative for improvement in the durability of concrete structures.

Improvement of Concrete Materials by Bacterial-Mediated Precipitation

2011 ◽  
Vol 306-307 ◽  
pp. 455-458 ◽  
Author(s):  
Pei Hao Li ◽  
Wen Jun Qu
Keyword(s):  
Laboratory Experiments ◽  
Carbonate Precipitation ◽  
Accelerated Carbonation ◽  
X Ray Diffraction ◽  
Capillary Water ◽  
X Ray ◽  
Microbial Carbonate ◽  
Microbial Carbonate Precipitation ◽  
Concrete Materials ◽  
Capillary Water Uptake

Microbial carbonate precipitation had been proposed as alternative technique for improvement in concrete materials. Laboratory experiments were conducted by bacterially mediated carbonate deposition on the surface and subsurface of concrete specimens. The crystal phase, morphology and growth of the crystal deposited on specimens as well as the efficiency of bonding and protection were analyzed by means of X-ray diffraction (XRD), scanning electron microscope (SEM), and ultrasonic test. Water absorption and the resistance of carbonation of concrete were analyzed by water absorptivity test and concrete accelerated carbonation test, respectively. Results show that phases of crystal are calcite and vaterite. The crystals are deposited uniformly on the surface of specimens. Biodeposotion effectively reduces capillary water uptake and carbonation rate constant.

scholarly journals Application of ground-penetrating radar technique to evaluate the waterfront location in hardened concrete

2016 ◽  
Author(s):  
Isabel Rodríguez-Abad ◽  
Gilles Klysz ◽  
Rosa Martínez-Sala ◽  
Jean Paul Balayssac ◽  
Jesús Mené-Aparicio
Keyword(s):  
Ground Penetrating Radar ◽  
Concrete Structures ◽  
Hardened Concrete ◽  
Concrete Durability ◽  
Water Penetration ◽  
Wave Parameters ◽  
Two Factors ◽  
Almost All ◽  
Ground Penetrating ◽  
Term Performance

Abstract. The long term performance of concrete structures is directly tied to two factors: concrete durability and strength. When assessing the durability of concrete structures, the study of the water penetration is paramount, because almost all reactions like corrosion, alkali-silica, sulfate, etc., which produce their deterioration, require the presence of water. Ground-penetrating radar (GPR) has shown to be very sensitive to water variations. On this basis, the objective of this experimental study is, firstly, to analyze the correlation between the water penetration depth in concrete samples and the GPR wave parameters. To do this, the samples were immersed into water for different time intervals and the wave parameters were obtained from signals registered when the antenna was placed on the immersed surface of the samples. Secondly, a procedure has been developed to be able to determine, from those signals, the reliability in the detection and location of waterfront depths. The results have revealed that GPR may have an enormous potential in this field, because excellent agreements were found between the correlated variables. In addition, when comparing the waterfront depths calculated from GPR measurements and those visually registered after breaking the samples, we observed that they totally agreed when the waterfront was more than 4 cm depth.

Durability of Concrete Structures

2015 ◽  
pp. 553-597 ◽  
Author(s):  
Xianglin Gu ◽  
Xianyu Jin ◽  
Yong Zhou
Keyword(s):  
Concrete Structures ◽  
Durability Of Concrete

scholarly journals Performance Evaluation of Ordinary Portland Cement with GGBFS and Portland Slag Cement at Same GGBFS Replacement Level in Concrete

2018 ◽  
Vol 203 ◽  
pp. 06004
Author(s):  
Ramesh Babu Chokkalingam ◽  
Manikandan Rajakannu
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Concrete Structures ◽  
Blended Cement ◽  
Mineral Admixtures ◽  
Slag Cement ◽  
Control Practice ◽  
Cement Manufacturing ◽  
Portland Slag Cement ◽  
Durability Of Concrete

Literature review indicates that the usage of mineral admixtures (Fly ash, Ground Granulated Blast Furnace Slag, Silica Fume and Rice Husk ash) significantly improves the durability of concrete structures. Though it is reported as best alternative materials for improving durability of concrete structures, it was not very well received in government projects in India till 1990. However, for the past two decades, the usage of mineral admixtures directly or in the form of blended cement in concrete have significantly increased. Major concern of using mineral admixtures which was persisting among majority of the Ordinary Portland Cement (OPC) users are (i) delayed setting and strength gain, affecting the rate of construction, (ii) inconsistent in quality of mineral admixtures, mostly happened in site blending (iii) no established results pertains to Indian condition. In India, mostly the usage of mineral admixtures in concrete are used as a replacement for OPC, specifically in Ready Mix Concrete and site batching plant. However, few literature have reported that usage of mineral admixtures in the form of blended cement which is made at cement manufacturing plant by either intergrinding or blending will exhibits better concrete properties due to consistent quality and better quality control practice followed. Hence, the authors have undertaken this study to investigate the performance of mineral admixtures (only GGBFS) as direct replacement materials and as blended cement in concrete. In order to understand in detail, both as replacement of OPC and in the form of PSC, was undertaken on various cement content in concrete, i.e., 300, 320, 340, 360, 380 kg/m3. Results of compressive strength at various age of curing indicates that usage of GGBFS in the form of Portland Slag Cement (PSC) shows better performance than as a replacement of OPC in concrete.

Durability of Concrete Structure Research and Development Direction

2010 ◽  
Vol 44-47 ◽  
pp. 2346-2353
Author(s):  
Lei Jiang ◽  
Ji Tao Yao ◽  
Ren Xin ◽  
Wei Li
Keyword(s):  
Research And Development ◽  
Concrete Structure ◽  
International Research ◽  
Concrete Structures ◽  
Future Research ◽  
Development Direction ◽  
The World ◽  
Four Levels ◽  
Structure Research ◽  
Durability Of Concrete

Currently, durability of concrete structures is a hot area of civil engineering. This paper reviews the background to the study of concrete and the current international research developments. Recent accomplishments in the world are summarized on four levels—environment, materials, components, structure. Finally, directions of future research are also proposed.

Durability in Cold Area of Prefabricated Concrete Structures

2014 ◽  
Vol 638-640 ◽  
pp. 1317-1321
Author(s):  
Ya Bo Wang ◽  
Lei Qian ◽  
Gao Feng Dou ◽  
Chuan Hao Xi ◽  
Han Ting Liu
Keyword(s):  
Failure Mechanism ◽  
Influencing Factors ◽  
Concrete Structure ◽  
Concrete Structures ◽  
Cold Regions ◽  
Factors Affecting ◽  
Cold Area ◽  
Durability Of Concrete

The factors affecting durability of concrete structures is described in This paper .It is pointed out here that is the concept of durability in prefabricated concrete structure , the influencing factors and failure mechanism in cold regions. It is proposed which are the methods and corresponding measures to enhance the durability of concrete structures.

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