Self-healing bacterial mortar with calcium lactate and improved properties

The advancing technologies of self-healing concrete focus on reversing and repairing the micro-cracks that form in concrete at early ages, increasing the durability of the structure. The utilization of the metabolic properties of bacteria in bacteria-based self-healing mortar has yielded promising r...

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Autores principales:	Galishnikova Vera, ELROBA SHERIF, Nassar Mohamed, Sakna Ahmed
Formato:	article
Lenguaje:	EN
Publicado:	Peter the Great St. Petersburg Polytechnic University 2021
Materias:	crack self healing bacterial mortar bio-cement mechanical properties permeability scanning electron microscopy calcite precipitation Engineering (General). Civil engineering (General) TA1-2040
Acceso en línea:	https://doaj.org/article/2b58e96d2875411789dd6216f283ec84
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spelling	oai:doaj.org-article:2b58e96d2875411789dd6216f283ec842021-11-12T15:54:04ZSelf-healing bacterial mortar with calcium lactate and improved properties2712-817210.34910/MCE.105.3https://doaj.org/article/2b58e96d2875411789dd6216f283ec842021-09-01T00:00:00Zhttp://engstroy.spbstu.ru/article/2021.105.03/https://doaj.org/toc/2712-8172The advancing technologies of self-healing concrete focus on reversing and repairing the micro-cracks that form in concrete at early ages, increasing the durability of the structure. The utilization of the metabolic properties of bacteria in bacteria-based self-healing mortar has yielded promising results in the reduction of cracks. Two species of bacteria Bacillus sphaericus (BS), Bacillus pasteurii (BP) were used in this study and patched at a ratio of cement weight in addition to Calcium Lactate being added as nutrition of bacteria. Setting time test was performed to measure the effect of bacteria on fresh mortar properties. The bacterial mixtures were compared to control mix to study their behavior under the influence of permeability test, compressive strength test, flexural strength test, sulfate resistance test and acid resistance test. Also, the restoration of bacterial mixes was tested. Furthermore, advanced technique were employed to evaluate the influence of bacteria addition, e.g. Scanning Electron Microscope (SEM). The cell concentration of Bacillus sphaericus (BS) and Bacillus pasteurii (BP) of all bacterial mortar mixes were counted. The bacteria nutrition acts as accelerator of cement pastes for initial setting time for all bacterial mortar compared to control mortar, while acts as a retarder of cement pastes for final setting time for all bacterial mortar compared to the control samples. Rate of water Absorption decreased with time and became nearly impermeable for BS60 and BP60 at the age of 120 days. Compressive strength of BS60 at 120 days age increased by 124 % compared to the control specimens. Flexural strength value of BS30 at the age of 120 days increased by 168 % compared to control mortar. Results showed that BP60 had a high ability to resist salts and acids. SEM proved that the bacterial mortar had less voids than that of control mortar. Microbial Induced Calcite Precipitation (MICP) is responsible for filling up the pores in mortar and hence decreased the rate of water absorption and the capillary permeability coefficient, while increasing the compressive and flexural strength for bacterial mortar.Galishnikova VeraELROBA SHERIFNassar MohamedSakna AhmedPeter the Great St. Petersburg Polytechnic Universityarticlecrackself healingbacterial mortarbio-cementmechanical propertiespermeabilityscanning electron microscopycalcite precipitationEngineering (General). Civil engineering (General)TA1-2040ENMagazine of Civil Engineering, Vol None, Iss 05 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	crack self healing bacterial mortar bio-cement mechanical properties permeability scanning electron microscopy calcite precipitation Engineering (General). Civil engineering (General) TA1-2040
spellingShingle	crack self healing bacterial mortar bio-cement mechanical properties permeability scanning electron microscopy calcite precipitation Engineering (General). Civil engineering (General) TA1-2040 Galishnikova Vera ELROBA SHERIF Nassar Mohamed Sakna Ahmed Self-healing bacterial mortar with calcium lactate and improved properties
description	The advancing technologies of self-healing concrete focus on reversing and repairing the micro-cracks that form in concrete at early ages, increasing the durability of the structure. The utilization of the metabolic properties of bacteria in bacteria-based self-healing mortar has yielded promising results in the reduction of cracks. Two species of bacteria Bacillus sphaericus (BS), Bacillus pasteurii (BP) were used in this study and patched at a ratio of cement weight in addition to Calcium Lactate being added as nutrition of bacteria. Setting time test was performed to measure the effect of bacteria on fresh mortar properties. The bacterial mixtures were compared to control mix to study their behavior under the influence of permeability test, compressive strength test, flexural strength test, sulfate resistance test and acid resistance test. Also, the restoration of bacterial mixes was tested. Furthermore, advanced technique were employed to evaluate the influence of bacteria addition, e.g. Scanning Electron Microscope (SEM). The cell concentration of Bacillus sphaericus (BS) and Bacillus pasteurii (BP) of all bacterial mortar mixes were counted. The bacteria nutrition acts as accelerator of cement pastes for initial setting time for all bacterial mortar compared to control mortar, while acts as a retarder of cement pastes for final setting time for all bacterial mortar compared to the control samples. Rate of water Absorption decreased with time and became nearly impermeable for BS60 and BP60 at the age of 120 days. Compressive strength of BS60 at 120 days age increased by 124 % compared to the control specimens. Flexural strength value of BS30 at the age of 120 days increased by 168 % compared to control mortar. Results showed that BP60 had a high ability to resist salts and acids. SEM proved that the bacterial mortar had less voids than that of control mortar. Microbial Induced Calcite Precipitation (MICP) is responsible for filling up the pores in mortar and hence decreased the rate of water absorption and the capillary permeability coefficient, while increasing the compressive and flexural strength for bacterial mortar.
format	article
author	Galishnikova Vera ELROBA SHERIF Nassar Mohamed Sakna Ahmed
author_facet	Galishnikova Vera ELROBA SHERIF Nassar Mohamed Sakna Ahmed
author_sort	Galishnikova Vera
title	Self-healing bacterial mortar with calcium lactate and improved properties
title_short	Self-healing bacterial mortar with calcium lactate and improved properties
title_full	Self-healing bacterial mortar with calcium lactate and improved properties
title_fullStr	Self-healing bacterial mortar with calcium lactate and improved properties
title_full_unstemmed	Self-healing bacterial mortar with calcium lactate and improved properties
title_sort	self-healing bacterial mortar with calcium lactate and improved properties
publisher	Peter the Great St. Petersburg Polytechnic University
publishDate	2021
url	https://doaj.org/article/2b58e96d2875411789dd6216f283ec84
work_keys_str_mv	AT galishnikovavera selfhealingbacterialmortarwithcalciumlactateandimprovedproperties AT elrobasherif selfhealingbacterialmortarwithcalciumlactateandimprovedproperties AT nassarmohamed selfhealingbacterialmortarwithcalciumlactateandimprovedproperties AT saknaahmed selfhealingbacterialmortarwithcalciumlactateandimprovedproperties
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Self-healing bacterial mortar with calcium lactate and improved properties

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