Pre-Crack Behaviours of Cement Paste Containing Bacillus pseudofirmus ATCC 700159

2019 ◽  
Vol 801 ◽  
pp. 371-376
Author(s):  
Rachit Lomsri ◽  
Athika Wongkvanklom ◽  
Prinya Chindaprasirt ◽  
Ampol Wongsa ◽  
Duangkanok Tanangteerapong
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Partial Replacement ◽  
Self Healing ◽  
Test Results ◽  
Carbonate Ion ◽  
Lime Water ◽  
Pass Through ◽  
The One ◽  
Cracked Specimens

The compressive strength of cement paste specimens containing Bacillus pseudofirmus ATCC 700159 was investigated in order to study the self-healing ability in cement specimens. A partial replacement of bacteria suspension by 10%, 20%, 30% and 40% by weight was mixed into the cement paste before casting. At age 28 days of curing in lime water, cement paste specimens were pre-cracked by 40% of maximum compressive strength in order to make the crack allowing moisture and air to pass through. After that, these specimens were left curing in the air until 60 days prior to the compressive test. Results showed that the specimens containing bacteria had a potential to form a new compound which was created by bacteria. XRD and FTIR analysis proved that bacteria could produce carbonate ion and therefore, combined with calcium ion in cement paste becoming calcium carbonate compound. This leads to the increase in compressive strength of pre-cracked specimens where the one with 40% bacteria giving satisfactory results of self-healing cement.

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.

scholarly journals Mechanical Properties and Microstructural Features using Stone Dust as a Partial Replacement of Sand

2019 ◽  
Vol 8 (6) ◽  
pp. 5232-5237
Keyword(s):  
Mechanical Properties ◽  
Economic Growth ◽  
Sustainable Development ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Natural Resources ◽  
Strength Test ◽  
Partial Replacement ◽  
Test Results ◽  
Stone Dust

Today’s world is always leads to development in technology as well as the economic growth though sometime these will affect the environment badly. That’s why world environmental commission coined the termed called sustainable development where development takes place without hampering the others’ needs. Concrete industry is rapidly growing industry in India which consumes lots of natural resources during the production of concrete. Here Stone dust is used as a sustainable material in place of sand partially. M25 grade of concrete has been chosen for the experiments. Different mechanical properties of concrete like compressive strength, Split tensile, flexural strength etc. and Microstructural features like SEM, EDX have been included in this study. Compressive Strength and flexural strength test results shown the increase in the strength. Sulphate Resistance Properties have been tested by curing the cubes in the MgSO4 solution and increase in weight has been observed. Similarities are found in the SEM pictures

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 Effect of Waste Clay Brick Powder on Physical and Mechanical Properties of Cement Paste

2021 ◽  
Vol 15 (1) ◽  
pp. 370-380
Author(s):  
David Sinkhonde ◽  
Richard Ocharo Onchiri ◽  
Walter Odhiambo Oyawa ◽  
John Nyiro Mwero
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Partial Replacement ◽  
Clay Brick ◽  
X Ray ◽  
Cement Replacement ◽  
Clay Bricks ◽  
Brick Powder ◽  
Scanning Electron

Background: Investigations on the use of waste clay brick powder in concrete have been extensively conducted, but the analysis of waste clay brick powder effects on cement paste is limited. Materials and Methods: This paper discusses the effects of waste clay brick powder on cement paste. Fragmented clay bricks were grounded in the laboratory using a ball mill and incorporated into cementitious mixes as partial replacement of Ordinary Portland Cement. Workability, consistency, setting time, density and compressive strength properties of paste mixes were investigated to better understand the impact of waste clay brick powder on the cementitious paste. Four cement replacement levels of 2.5%, 5%, 7.5% and 10% were evaluated in comparison with the control paste. The chemical and mineral compositions were evaluated using X-Ray Fluorescence and X-Ray Diffractometer, respectively. The morphology of cement and waste clay brick powder was examined using a scanning electron microscope. Results: The investigation of workability exhibited a reduction of slump attributed to the significant addition of waste clay brick powder into the cementitious mixes, and it was concluded that waste clay brick powder did not significantly influence the density of the mixes. In comparison with the control paste, increased values of consistency and setting time of cement paste containing waste clay brick powder confirmed the information available in the literature. Conclusion: Although waste clay brick powder decreased the compressive strength of cement paste, 5% partial cement replacement with waste clay brick powder was established as an optimum percentage for specimens containing waste clay brick powder following curing periods of 7 and 28 days. Findings of chemical composition, mineral composition and scanning electron microscopy of waste clay brick powder demonstrated that when finely ground, fragmented clay bricks can be used in concrete as a pozzolanic material.

High Volume Slag and Slag-Fly Ash Blended Cement Pastes Containing Nano Silica

2019 ◽  
Vol 967 ◽  
pp. 205-213
Author(s):  
Faiz U.A. Shaikh ◽  
Anwar Hosan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Cement Paste ◽  
Ordinary Portland Cement ◽  
Blended Cement ◽  
High Volume ◽  
Ash Content ◽  
Partial Replacement ◽  
Nano Silica ◽  
Cement Pastes

This paper presents the effect of nanosilica (NS) on compressive strength and microstructure of cement paste containing high volume slag and high volume slag-fly ash blend as partial replacement of ordinary Portland cement (OPC). Results show that high volume slag (HVS) cement paste containing 60% slag exhibited about 4% higher compressive strength than control cement paste, while the HVS cement paste containing 70% slag maintained the similar compressive strength to control cement paste. However, about 9% and 37% reduction in compressive strength in HVS cement pastes is observed due to use of 80% and 90% slag, respectively. The high volume slag-fly ash (HVSFA) cement pastes containing total slag and fly ash content of 60% exhibited about 5%-16% higher compressive strength than control cement paste. However, significant reduction in compressive strength is observed in higher slag-fly ash blends with increasing in fly ash contents. Results also show that the addition of 1-4% NS improves the compressive strength of HVS cement paste containing 70% slag by about 9-24%. However, at higher slag contents of 80% and 90% this improvement is even higher e.g. 11-29% and 17-41%, respectively. The NS addition also improves the compressive strength by about 1-59% and 5-21% in high volume slag-fly ash cement pastes containing 21% fly ash+49%slag and 24% fly ash+56%slag, respectively. The thermogravimetric analysis (TGA) results confirm the reduction of calcium hydroxide (CH) in HVS/HVSFA pastes containing NS indicating the formation of additional calcium silicate hydrate (CSH) gels in the system. By combining slag, fly ash and NS in high volumes e.g. 70-80%, the carbon footprint of cement paste is reduced by 66-76% while maintains the similar compressive strength of control cement paste. Keywords: high volume slag, nanosilica, compressive strength, TGA, high volume slag-fly ash blend, CO2 emission.

scholarly journals Effect of basalt powder addition on properties of mortar

2019 ◽  
Vol 262 ◽  
pp. 06002 ◽  
Author(s):  
Magdalena Dobiszewska ◽  
Waldemar Pichór ◽  
Paulina Szołdra
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Beneficial Effect ◽  
Cement Paste ◽  
Cement Hydration ◽  
Asphalt Mixture ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Freeze Resistance ◽  
Powder Addition

The study evaluates the use of waste basalt powder as a replacement of cement to enhance hydration of cement and mortar properties. The basalt powder is a waste resulting from preparation of aggregate used in asphalt mixture production. Previous studies have shown that analysed waste used as a fine aggregate replacement has a beneficial effect on some properties of mortar and concrete, i.e. compressive strength, flexural strength and freeze resistance. The present study shows the results of the research concerning the modification of cement paste and mortar with basalt powder. The modification consists in adding the powder waste as a partial replacement of cement. The percentages of basalt powder in this research are 0-40% and 0-20% by mass of cement in the pastes and mortars respectively. The experiments were carried out to determine the influence of basalt powder on cement hydration, as well as compressive and flexural strength. Results indicate that addition of basalt powder as a replacement of cement leads to deterioration of compressive strength. The flexural strength of mortar is improved in some cases. Waste basalt powder only slightly influences the cement hydration.

BEHAVIOR OF M 50 GRADE SELF-COMPACTING CONCRETE DEVELOPED USING PORTLAND SLAG CEMENT AND METAKAOLIN

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Sravya Nalla ◽  
Janardhana Maganti ◽  
Dinakar Pasla
Keyword(s):  
Compressive Strength ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Test Results ◽  
Slag Cement ◽  
Self Compacting Concrete ◽  
Destructive Testing ◽  
Compressive Strength Test ◽  
Portland Slag Cement ◽  
Strength And Durability

Self-compacting concrete (SCC) is a revolutionary development in concrete construction. The addition of mineral admixtures like metakaolin, which is a highly reactive pozzolana to the SCC mixes, gives it superior strength and durability. The present work is an effort to study the behavior of M50 grade SCC by partial replacement of Portland Slag Cement (PSC) with metakaolin. Its strength and durability aspects are comparable with a controlled concrete (without replacement of cement). In the present work, a new mix design methodology based on the efficiency of metakaolin is adopted. The optimum percentage replacement of cement with metakaolin is obtained based on compressive strength test results. The influence of metakaolin on the workability, compressive strength, splitting tensile strength and flexural strength of SCC and its behavior when subjected to elevated temperature was investigated through evaluation against controlled concrete and non-destructive testing. From the test results, it was observed that incorporation of metakaolin at an optimum dosage satisfied all the fresh properties of SCC and improved both the strength and durability performance of SCC compared to controlled concrete.

scholarly journals Investigative Study of Partial Replacement of Cement with Bio-Cement, Fly Ash and Natural Pozzolans

2021 ◽  
Vol 12 (1S) ◽  
pp. 432-436
Author(s):  
Dr.Sarvesh, Et. al.
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Main Property ◽  
Partial Replacement ◽  
Self Healing ◽  
Split Tensile Strength ◽  
Conventional Concrete ◽  
Quality Properties ◽  
Natural Pozzolans ◽  
The Impact

Concrete is usually a combination of cement, coarse particles (aggregates and Sand) and water. It is used to design and improve the infrastructures.It is used to design and improve the infrastructures. Concrete has many advantages and disadvantage. The main property that is characteristic to a concrete’s workability is its compressive strength. Only through this single test, one can judge if cementing has been done appropriately. Possible advancements for development include the use of non-traditional and creative materials, and the reuse of waste materials with a specific end goal to replenish the absence of specific assets and to discover alternative ways to monitor the Earth..This investigation concentrate on Compressive strength, flexural and split tensile strength of Conventional Concrete (CC) and Class C fly ash remains with bio-cement and natural pozzolans to consider the impact of bio-concrete with blend extents of 0%,0.25%,0.5%,1% and 1.5% on quality properties. Moreover, effective self-healing usually occurred due to the use of polymers, microorganism and additional cementing material. It is the key issue to find out the self-healing efficiency’s effect to sealing the crack width successfully. And good resistance was observed during the bacterial chemical process against the freeze and thaw attacks.

scholarly journals PENGARUH PENAMBAHAN SERAT IJUK PADA PAVING BLOCK BERBAHAN PLASTIK HDPE

2021 ◽  
Vol 7 (3) ◽  
pp. 178-182
Author(s):  
Denny Meisandy Hutauruk ◽  
Muhammad Irwansyah ◽  
Akbar Alfa
Keyword(s):  
Compressive Strength ◽  
Composite Fiber ◽  
Plastic Waste ◽  
The Other ◽  
Test Results ◽  
Complex Issue ◽  
Palm Fiber ◽  
Fiber Plastic ◽  
The One ◽  
Average Compressive Strength

The waste problem continues to be a complex issue. On the one hand, the use of plastic still cannot be abandoned by humans, but on the other hand the waste produced is very difficult to decompose. In Indonesia, in 2015 the amount of waste reached 64 million tons / year. Palm fiber is one of the materials that can be used as composite fiber. In this study, a research will be conducted on the manufacture of paving blocks made from HDPE plastic combined with variations of 0%, 1%, 2% and 3% palm fiber. Plastic waste is melted and put into a mold and then combined with palm fiber. From the test results, the highest compressive strength (2% fiber variation) was 45.91 kg/cm2 and the average compressive strength was 45.28 kg/cm2. This compressive strength is under the minimum compressive strength standard of SNI   Permasalahan sampah masih terus menjadi isu kompleks. Di satu sisi, penggunaan plastik masih belum bisa ditinggalkan manusia, namun di sisi lain sampah yang dihasilkan sangat sulit terurai. Di indonesia, pada tahun 2015 tercatat banyaknya sampah mencapai 64 juta ton/tahun. Ijuk merupakan salah satu material yang dapat digunakan sebagai serat komposit. Pda penelitian ini akan dilakukan penelitian mengenai pembuatan paving block berbahan dasar plastik HDPE yang dikombinasikan dengan variasi serat ijuk 0%, 1%, 2 % dan 3%. Limbah plastik dilelehkan dan dimasukkan ke dalam cetakan lalu dipadukan dengan serat ijuk. Dari hasil pengujian, didapatkan kuat tekan tertinggi (variasi serat 2%) sebesar 45,91 kg/cm2 dan kuat tekan rata-ratanya sebesar 45,28 kg/cm2. Kuat tekan ini berada di bawah standar kuat tekan minimal dari SNI.

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.

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