scholarly journals AN INVESTIGATION ON THE USE OF BACILLUS SUBTILIS HU58 IN CEMENT MORTAR

2017 ◽  
Vol 7 (2) ◽  
pp. 1-8
Author(s):  
Nguyen Ngoc Tri Huynh ◽  
Nguyen Khanh Son
Keyword(s):  
Bacillus Subtilis ◽  
Calcium Carbonate ◽  
Portland Cement ◽  
Cement Mortar ◽  
Cement Matrix ◽  
Self Healing ◽  
Curing Time ◽  
Mortar Sample ◽  
New Type ◽  
Compressive And Flexural Strengths

Literature studies reveal the fact that incorporating bacteria into cement matrix could generate the formation of precipitated product of calcium carbonate. In this work, a new type of microorganism Bacillus subtilis HU58 was used as mixing component in formulating mortar sample of Portland cement and the effectiveness of self-healing character after 1 year of curing time was observed. Results showed the consequence in the enhancement of both compressive and flexural strengths of bacteria-modified mortar while comparing to a controlled mortar: 60MPa>56MPa (in compression) and 11MPa >9MPa (in flexion). Furthermore, those pre-existing artificial cracks 1mm in width of the prismatic mortar 40x40x160mm filled up partially (self-healing) by mineral glue.

scholarly journals Bacillus Subtilis as Self-Healing Agent in Cement Mortar: The Effect of Curing Time and Amount of Calcium Lactate on Strength

2021 ◽  
Vol 40 (4) ◽  
pp. 889-897
Author(s):  
Sohail Muhammad ◽  
Humair Ahmed Siddiqui
Keyword(s):  
Compressive Strength ◽  
Bacillus Subtilis ◽  
Calcium Carbonate ◽  
Cement Mortar ◽  
Calcium Lactate ◽  
Self Healing ◽  
Curing Time ◽  
Healing Agent ◽  
Cause Of Failure ◽  
The Cost

Crack growth is a major cause of failure in structures that are made using cement and concrete. Healing of these cracks can increase the life span of structures. In the present study micro-organism based self-healing of structures is studied. A commonly occurring micro-organism bacterium called Bacillus Subtilis, is used in the manufacturing of cement mortar blocks as a self-healing agent for cement mortar blocks, with the use of Calcium Lactate as feed for bacteria. In the first step, colonies of Bacillus Subtilis were grown and added with calcium lactate to produce a solution. The solution was then kept for one week to observe the metabolic product of Bacillus Subtilis. It was found that the bacterial product was composed of CaCO3 and thus the bacteria is suitable to be used as self-healing agent. Self-healing cement mortar blocks were made by adding Bacteria and Calcium Lactate with usual ingredients of cement mortar, i.e. cement, sand and water. It was found that the bacteria were also effective in converting Calcium Lactate to Calcium Carbonate, when mixed in cement mortar blocks. It was observed that the pores of cement mortar blocks were filled by Calcium Carbonate and that cracks get healed by the deposition of Calcium Carbonate in the cracks. Cement mortar blocks, with and without healing agent, were made to compare the effect of curing time. The samples were tested after seven, fourteen and twenty-eight days to compare the effect of healing agent. All the samples with the healing agent showed a higher compressive strength in comparison with the samples that were made without healing agent. Different percentages of Calcium Lactate, ranging from 1-7% were also used to find the best composition for future use. It was found that the compressive strength was increasing up to 5% while above 5% the increase was marginal thus it is proposed that Calcium Lactate should be used in between 5-7 % to reduce the cost of self-healing cement in construction industry.

Fluid Transport Mechanisms in Portland Cement Mortar Modified with PVA and Nano Montmorillonite

2013 ◽  
Vol 687 ◽  
pp. 311-315 ◽  
Author(s):  
Teresa María Piqué ◽  
Luis Fernandez Luco ◽  
Analía Vázquez
Keyword(s):  
Tensile Strength ◽  
Portland Cement ◽  
Construction Industry ◽  
Fluid Transport ◽  
Cement Mortar ◽  
Drying Shrinkage ◽  
Cement Matrix ◽  
Poly Vinyl Alcohol ◽  
Cement Mortars ◽  
Compressive And Flexural Strengths

The development of new materials for specific applications is an increasing field in the construction industry, so is the employment of nanotechnology for this goal. When poly(vinyl alcohol) (PVA) is added to a Portland cement mortar, a film is formed in between the hydration products. This film has low elasticity modulus and high tensile strength and it enhances the mortar’s mechanical properties in the fresh and hardened states. The addition of nano montmorillonites (MMT) gives the polymer a better compatibility with the cement matrix. In this work, the changes in the microstructure of Portland cement mortars modified with PVA and PVA with MMT are assessed by means of transport of fluids capacity as an indicator. The reference is a standard mortar according to EN 196-1. The parameters measured are: weight loss under drying and air permeability. Complementary measures, such as compressive and flexural strengths and drying shrinkage have also been performed. From the obtained results, it can be concluded that the inclusion PVA + MMT to Portland cement mortar doesn’t affect the microstructure, when compared with Portland cement mortar with PVA, and even increase its tensile strength.

scholarly journals Use of Bio-Active Bacillus subtilis bacteria to form self-healing concrete

2014 ◽  
Vol 17 (1) ◽  
pp. 76-86
Author(s):  
Huynh Ngoc Tri Nguyen ◽  
Son Khanh Nguyen
Keyword(s):  
Bacillus Subtilis ◽  
Smart Materials ◽  
Cement Mortar ◽  
A Priori ◽  
Xrd Analysis ◽  
Concrete Durability ◽  
Self Healing ◽  
Curing Time ◽  
Petri Plate ◽  
Time Specific

Self-healing concrete or bio-concrete is considered as one kind of “living” smart materials. Recently, bio-concrete has become more attractive to researchers around the world because of its promising future in improving concrete durability. In this study, we investigate the role of Bacillus subtilis in healing cracked cement. Bacillus subtilis 109cfu/g and 1011cfu/g, respectively, was tested in the different scale sample: normal condition in Petri plate, binding in cement hydrate product and dispersing in cement mortar 40x40x160mm. From the result of XRD analysis and microscopy (OP, SEM), calcite precipitates were found after curing time of 7, 14, and 28 days. In the presence of this calcite deposit, both results of compressive and flexural properties of cement mortar increased up to 30%. The self-healing effect was tested with a priori crack 0.5mm in large of a prismatic sample during 14 days of curing time. Specific discussion on the obtained results permit us to extend this study for concrete sample.

scholarly journals Bioprecipitation of calcium carbonate by Bacillus subtilis and its potential to self-healing in cement-based materials

2020 ◽  
Vol 18 (5) ◽  
Author(s):  
Héctor Ferral Pérez ◽  
Mónica Galicia García
Keyword(s):  
Bacillus Subtilis ◽  
Calcium Carbonate ◽  
Building Materials ◽  
Soil Stabilization ◽  
Amorphous Material ◽  
Crystallinity Index ◽  
Self Healing ◽  
Semi Solid ◽  
A Minor ◽  
Novel Applications

In recent years, biological mineralization has been implemented as a viable option for the elaboration of new building materials, protection and repair of concrete by self-healing, soil stabilization, carbon dioxide capture, and drug delivery. Biogenic mineralization of calcium carbonate (CaCO3) induced by bacterial metabolism has been proposed as an effective method. The objective of the present study was to characterize the bioprecipitation of CaCO3 crystals by Bacillus subtilis in a semi-solid system. The results show that CaCO3 crystals were produced by day 3 of incubation. The prevalent crystalline polymorph was calcite, and in a minor proportion, vaterite. The presence of amorphous material was also detected (amorphous CaCO3 (ACC)). Finally, the crystallinity index was 81.1%. This biogenic calcium carbonate does not decrease pH and does not yield chloride formation. Contrary, it increases pH values up to 10, which constitutes and advantage for implementations at reinforced concrete. Novel applications for biogenic calcium carbonate derived from Bacillus subtilis addressing self-healing, biocementation processes, and biorestoration of monuments are presented.  

Bio-inspired self-healing cementitious mortar using Bacillus subtilis immobilized on nano-/micro-additives

2018 ◽  
Vol 30 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Rao Arsalan Khushnood ◽  
Siraj ud din ◽  
Nafeesa Shaheen ◽  
Sajjad Ahmad ◽  
Filza Zarrar
Keyword(s):  
Compressive Strength ◽  
Bacillus Subtilis ◽  
Iron Oxide ◽  
Cement Mortar ◽  
Healing Process ◽  
Main Concern ◽  
Scanning Electron Micrographs ◽  
Self Healing ◽  
Micro Cracks ◽  
Cracked Specimens

Bio-inspired self-healing strategies are much innovative and potentially viable for the production of healable cement mortar matrix. The present research explores the feasibility of gram-positive “Bacillus subtilis” microorganisms in the effective healing of nano-/micro-scale-induced structural and non-structural cracks. The main concern related to the survival of such microorganisms in cementitious environment has been successfully addressed by devising proficient immobilization scheme coherently. The investigated immobilizing media includes iron oxide nano-sized particles, micro-sized limestone particles, and milli-sized siliceous sand. The effect of induced B. subtilis microorganisms immobilized on nano-micro-additives was analyzed by the quantification of average compressive resistance of specimens (ASTM C109) and healing evaluation. The healing process was mechanically gauged by compressive strength regain of pre-cracked specimens after the healing period of 28 days. The pre-cracking load was affixed at 80% of ultimate compressive stress “[Formula: see text]” while the age of pre-cracking was kept variable as 3, 7, 14, and 28 days to precisely correlate healing effectiveness as the function of cracking period. The healing mechanism was further explored by examining the healed micro-crack using field emission scanning electron micrographs, energy dispersive x-ray spectrographs, and thermogravimetry. The results revealed that B. subtilis microorganisms contribute extremely well in the improvement of compressive strength and efficient healing process of pre-cracked cement mortar formulations. The iron oxide nano-sized particles were found to be the most effective immobilizer for preserving B. subtilis microbes till the generation of cracks followed by siliceous sand and limestone particles. The micro-graphical and chemical investigations endorsed the mechanical measurements by evidencing calcite precipitation in the induced nano-/micro-cracks as a result of microbial activity.

Strength of Portland Cement with Several Composition of Bottom Ash in Different Fineness with Curing Time of 28 Days

2016 ◽  
Vol 857 ◽  
pp. 311-313
Author(s):  
Ng Hooi Jun ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin ◽  
Soo Jin Tan ◽  
Mohd Firdaus Omar ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Portland Cement ◽  
Environmental Effects ◽  
Coal Combustion ◽  
Cement Mortar ◽  
Bottom Ash ◽  
Curing Time ◽  
Cement Replacement

Concrete is produced increasingly worldwide and accounting 10-20% emission of carbon dioxide. The potential long term opposing cost of environmental effects need to recognize. Residue of coal combustion ashes especially bottom ash will use to develop reuse application. This study focused on compressive strength of several composition of bottom ash as cement replacement in mortar. Curing of cement mortar techniques and duration also plays an important role and effects on the strength. The objective of this research is to examine the compressive strength of bottom ash in Portland cement under various compositions and fineness of bottom ash.

scholarly journals Biomineralization of Plastic Waste to Improve the Strength of Plastic-Reinforced Cement Mortar

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1949
Author(s):  
Seth Kane ◽  
Abby Thane ◽  
Michael Espinal ◽  
Kendra Lunday ◽  
Hakan Armağan ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Cement Mortar ◽  
Cementitious Materials ◽  
Plastic Waste ◽  
Cement Matrix ◽  
Carbonate Precipitation ◽  
Calcium Carbonate Precipitation ◽  
Plastic Pollution ◽  
Reinforced Cement ◽  
Type 3

The development of methods to reuse large volumes of plastic waste is essential to curb the environmental impact of plastic pollution. Plastic-reinforced cementitious materials (PRCs), such as plastic-reinforced mortar (PRM), may be potential avenues to productively use large quantities of low-value plastic waste. However, poor bonding between the plastic and cement matrix reduces the strength of PRCs, limiting its viable applications. In this study, calcium carbonate biomineralization techniques were applied to coat plastic waste and improved the compressive strength of PRM. Two biomineralization treatments were examined: enzymatically induced calcium carbonate precipitation (EICP) and microbially induced calcium carbonate precipitation (MICP). MICP treatment of polyethylene terephthalate (PET) resulted in PRMs with compressive strengths similar to that of plastic-free mortar and higher than the compressive strengths of PRMs with untreated or EICP-treated PET. Based on the results of this study, MICP was used to treat hard-to-recycle types 3–7 plastic waste. No plastics investigated in this study inhibited the MICP process. PRM samples with 5% MICP-treated polyvinyl chloride (PVC) and mixed type 3–7 plastic had compressive strengths similar to plastic-free mortar. These results indicate that MICP treatment can improve PRM strength and that MICP-treated PRM shows promise as a method to reuse plastic waste.

Natural Carbonation of Thermally Damaged Cement Mortar Studied by Thermogravimetric Analysis

2014 ◽  
Vol 529 ◽  
pp. 41-44
Author(s):  
Son Tung Pham ◽  
William Prince
Keyword(s):  
Heat Treatment ◽  
Calcium Carbonate ◽  
Thermogravimetric Analysis ◽  
Ambient Temperature ◽  
Cement Mortar ◽  
Self Healing ◽  
Healing Effect ◽  
Carbonation Process ◽  
Different Temperatures ◽  
Natural Carbonation

The objective of this study was to examine the natural carbonation that occurs during the cooling of thermally damaged cement mortar. Thermogravimetric analysis was used to follow mineralogical changes of CEM II mortar which was treated at different temperatures from 105 to 500°C. The results showed that, during the cooling to ambient temperature, by capturing CO2 from atmosphere the cement mortar tends to gain calcium carbonate from the loss of portlandite which was caused by heat treatment. This natural carbonation process allows the thermally damaged mortar to autonomously generate self-healing effect so that it can regain the initial properties.

scholarly journals The Effect of Exposure on the Autogenous Self-Healing of Ordinary Portland Cement Mortars

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3926 ◽  
Author(s):  
Magdalena Rajczakowska ◽  
Karin Habermehl-Cwirzen ◽  
Hans Hedlund ◽  
Andrzej Cwirzen
Keyword(s):  
Calcium Carbonate ◽  
Portland Cement ◽  
Crack Closure ◽  
Water Immersion ◽  
Pure Water ◽  
Healing Process ◽  
Silica Particles ◽  
The Self ◽  
Phase Identification ◽  
Self Healing

Exposure conditions are critical for the autogenous self-healing process of Portland cement based binder matrixes. However, there is still a significant lack of fundamental knowledge related to this factor. The aim of this paper was to investigate and understand the effects of various potentially applicable curing solutions on the efficiency of the crack closure occurring both superficially and internally. Four groups of exposures were tested, including exposure with different water immersion regimes, variable temperatures, application of chemical admixtures, and use of solutions containing micro particles. The self-healing process was evaluated externally, at the surface of the crack, and internally, at different crack depths with the use of optical and scanning electron microscopes (SEM). The phase identification was done with an energy dispersive spectrometer combined with the SEM. The results showed very limited self-healing in all pure water-based exposures, despite the application of different cycles, temperatures, and water volumes. The addition of a phosphate-based retarding admixture demonstrated the highest crack closure, both internally and externally. The highest strength recovery and a very good crack closure ratio was achieved in water exposure containing micro silica particles. The main phase observed on the surface was calcium carbonate, and internally, calcium silicate hydrate, calcium carbonate, and calcium phosphate compounds. Phosphate ions were found to contribute to the filling of the crack, most likely by preventing the formation of a dense shell composed of hydration phases on the exposed areas by crack unhydrated cement grains as well as by the additional precipitation of calcium and phosphate-based compounds. The micro sized silica particles presumably served as nucleation sites for the self-healing products growth. Changes in the chemical composition of the self-healing material were observed with a distance from the surface of the specimen.

Sign in / Sign up

Export Citation Format

Share Document