Effectiveness of Different Curing Media in Self-healing Process Monitored by Compressive Strength and Water Absorption of Cement Mortar

2021 ◽  
pp. 247-257
Author(s):  
Norfaniza Mokhtar ◽  
Wan Amizah Wan Jusoh ◽  
Muhammad Fitri Mah Hassan
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Cement Mortar ◽  
Healing Process ◽  
Self Healing

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.

Incorporation of Iraqi Rocks in the Production of Eco-Friendly Cement Mortar

2020 ◽  
Vol 38 (10A) ◽  
pp. 1522-1530
Author(s):  
Rawnaq S. Mahdi ◽  
Aseel B. AL-Zubidi ◽  
Hassan N. Hashim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Structural Properties ◽  
Mechanical Milling ◽  
Cement Mortar ◽  
Cement Mortars

This work reports on the incorporation of Flint and Kaolin rocks powders in the cement mortar in an attempt to improve its mechanical properties and produce an eco-friendly mortar. Flint and Kaolin powders are prepared by dry mechanical milling. The two powders are added separately to the mortars substituting cement partially. The two powders are found to improve the mechanical properties of the mortars. Hardness and compressive strength are found to increase with the increase of powders constituents in the cement mortars. In addition, the two powders affect water absorption and thermal conductivity of the mortar specimens which are desirable for construction applications. Kaolin is found to have a greater effect on the mechanical properties, water absorption, and thermal conductivity of the mortars than Flint. This behavior is discussed and analyzed based on the compositional and structural properties of the rocks powders.

scholarly journals A Study on Tannery Sludge as a Raw Material for Cement Mortar

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1562 ◽  
Author(s):  
Jurgita Malaiškienė ◽  
Olga Kizinievič ◽  
Viktor Kizinievič
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Cement Mortar ◽  
Ultrasonic Pulse Velocity ◽  
Xrd Analysis ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Raw Material ◽  
Tannery Sludge ◽  
Limit Values

The paper analyses the properties (chemical and mineral composition, microstructure, density, etc.) of recycled tannery sludge (TS) and the possibilities for using it in cement mortar mixture. Mortar specimens containing 3–12% of tannery sludge by weight of cement and 3–9% of tannery sludge by weight of sand were tested. Flowability, density, ultrasonic pulse velocity (UPV), flexural and compressive strength, water absorption and sorptivity of the mortar were analysed. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis of tannery sludge and mortar are presented. The tests revealed that replacement of 6% of cement with tannery sludge in the mix increased flexural and compressive strength and UPV values, whereas water absorption decreased. SEM and XRD analysis revealed that specimens with tannery sludge contained lower amounts of ettringite and higher amounts of portlandite; the obtained structure was denser and contained more calcium hydrosilicates (C-S-H). Chromium leaching values in cement mortars were found not to exceed the limit values set forth in Directive 2003/33/EC.

scholarly journals Characterization of Slag Cement Mortar Containing Nonthermally Treated Dried Red Mud

2019 ◽  
Vol 9 (12) ◽  
pp. 2510 ◽  
Author(s):  
Gyeongcheol Choe ◽  
Sukpyo Kang ◽  
Hyeju Kang
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Water Content ◽  
Red Mud ◽  
Absorption Rate ◽  
Cement Mortar ◽  
Slag Cement ◽  
X Ray ◽  
Water Absorption Rate ◽  
High Calcium

In this study, a method was suggested to produce dried powder from red mud (RM) sludge with 40%–60% water content without heating. The RM sludge is discharged from the Bayer process, which is used to produce alumina from bauxite ores. Nonthermally treated RM (NTRM) powder was produced by mixing RM sludge (50%), paper sludge ash (PSA, 35%), and high-calcium fly ash (HCFA, 15%). The physicochemical properties of NTRM were investigated by analyzing its water content, X-ray fluorescence spectra, X-ray diffraction patterns, and particle size. Moreover, to examine the applicability of NTRM as a construction material, slag cement mortar in which 20 wt% of the binder was replaced with NTRM was produced, and the compressive strength, porosity, and water absorption rate of the mortar were evaluated. Results indicated that NTRM of acceptable quality was produced when the water content in RM sludge decreased and CaO contained in PSA and HCFA reacted with moisture and formed portlandite. The NTRM-mixed mortar requires further examination in terms of durability because of the increased capillary voids and high water absorption rate, but its compressive strength is sufficient to enable its use in sidewalks, bike roads, and parking lots.

Development of Drainage Material Using Rice Husk Cement Mortar with Foam

2016 ◽  
Vol 700 ◽  
pp. 173-182
Author(s):  
Muhammad Munsif Ahmad ◽  
Fauziah Ahmad ◽  
Mastura Azmi
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Rice Husk ◽  
Cement Mortar ◽  
Construction Material ◽  
Foaming Agent ◽  
Infiltration Model ◽  
Aqueous Foam ◽  
Constant Head ◽  
Good Drainage

Nowadays, interest in developing environmental friendly construction material was increased. As the result, many researches have been done to make use of waste material for engineering purposes. This paper present the results of laboratory experiments on the potential of raw rice husk (RH) cement mortar with addition of foam as drainage material. Mechanical properties which are compressive strength, density, water absorption and porosity have been investigated in order to identify the potential of this material to function as drainage material. Total of eight set of sample were tested to determine those properties. Aqueous foam generated from chemical based foaming agent was used in this study to enhance the drainage ability and also reducing the density of the cement based mixture. More over to simulate the real application at site, an infiltration model was developed to determine the drainage and infiltration characteristic of this material. The permeability of the sample used in the infiltration model has been tested using constant head test to verify the validity of the infiltration model. From the result obtained, it can be concluded that the compressive strength and density of sample decreases with percentage of raw rice husk used while the additional of foam has further reducing the compressive strength and density. Both water absorption and porosity showing the opposite trend compared to the compressive strength. This drainage material can be pre-designed between 1.60N/mm2 – 10.12 N/mm2 for compressive strength, 1392kg/m3 - 1841kg/m3 for density, 21% - 34% for water absorption and 31% - 42% for porosity. From the result of infiltration model, it was observed that this material having good drainage ability with the permeability of 15% foamed rice husk sample is 1.57x10-3.

scholarly journals Study the Effects of Reactive Materials Replacement on Some Properties of Cement Mortar

2018 ◽  
Vol 6 (4) ◽  
pp. 183-190
Author(s):  
Mohammed J. Kadhim ◽  
Raeid K. Mohammed Jawad ◽  
Hamza M. Kamal
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Cement Mortar ◽  
Surface Hardness ◽  
Type I ◽  
Fine Aggregate ◽  
Curing Time ◽  
Natural Materials ◽  
Water To Cement Ratio ◽  
Water Absorption Test

This study involves natural--materials replacement and its reaction with cement mortar behavior for many mortar samples under variable curing time with constant water to cement ratio (W/C = 0.5).In this researchsomeproperties such as (compressive strength the surface hardness and water absorption test), were affected by adding small ratios ofpowder (from (RHA) and (BRP) particles)as replacements to the Ordinary Portland Cement (OPC) / type (I). The percentages of natural materials additives replacement on the mixture of mortar include (0, 5, 10, 15 and 20%) with constant (W/C) ratio. Also the amount of the fine aggregate used was three times the amount of cement. The results showed that, the compressive strength and splitting tensile strength and water absorption of the mortars for (replacement) gives better properties than mortar without replacement in all tests. Best enhancements in properties for mortars with pozzalanic replacements were achieved at (15%) for (RHA) and 10% for (RBP) replacement from weight of cement.

scholarly journals Effect of Bacteria Inoculums on Compressive Strength

2021 ◽  
Vol 8 (2) ◽  
pp. 59-63
Author(s):  
Pooja Bandekar ◽  
Sandhay Basavaraj ◽  
Prakash Mallappa Munnoli ◽  
Jyoti Gupta ◽  
Geeta Shetteppanavar ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Cement Mortar ◽  
Culture Collection ◽  
Self Healing ◽  
Cement Concrete ◽  
Calcite Precipitation ◽  
Chain Reaction ◽  
Colony Forming Units ◽  
Polymerase Chain ◽  
Strength And Durability

The use of bio-concrete is increasing in the present day context and researchers are working on strength and durability characteristics of concrete using bacteria species which have shown calcite precipitation. Three different species of bacteria namely P. Fluorescence, B. Pumilis and B. Subliis that have calcite precipitation properties have been investigated in this study. The investigations were carried first on cement mortar (CM) cubes using these three bacteria species suspension of 20%; 40% and 60% having colony forming units P. Fluorescence (108 CFU/ml), B. Pumilis (106 CFU/ml) and B. Subtilis (108 CFU/ml) respectively. The 40% suspension in all the three cases has shown increased compressive strength as compared to 20% and 60%. The compressive strength measured showed increase (CS) of 18%; 12% for P. Fluorescence; B. Subtilis and decrease of 35% with B. Pumilis respectively. B. Subtilis with optimized 40% suspension having CFU 10x108/ml showed 4.32% ; 5.56%; and 3.81% increase in CS of CC cubes with 3 days; 7 days and 28 days respectively and 5.92% overall increase in CS of CC cubes as compared to the 3 days CS of control cube. ABBREVIATIONSSDW: Sterile Distilled Water; SHC: Self-Healing Concrete; PCR: Polymerase Chain Reaction; BC: Bacterial Concrete; CP: Calcite precipitation; CS: Compressive Strength; CC: Cement Concrete; CM: Cement Mortar; MTCC: Microbial Type Culture Collection; CFU: Colony Forming Unit/ml

Effect of Nano silica on strength and water absorption of cement mortar Exposed low pressure environment

2021 ◽  
Vol 06 ◽  
Author(s):  
Ai Zhang ◽  
Yong Ge
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Water Absorption ◽  
Cement Mortar ◽  
Strength Loss ◽  
Low Pressure ◽  
Low Humidity ◽  
Strength And Durability ◽  
Humidity Environment

Background: Buildings in high altitude region often face low pressure and low humidity service environment, which has a great impact on the mechanical properties and durability of cement-based materials. Objective: In this paper, the effects of nano-silica (NS) on the strength and water absorption of cement mortar exposed to the low pressure and low humidity environment were studied. Methods: Mechanical properties (compressive strength and flexural strength) and durability (water absorption) were measured. And the hydration degree of cement was tested to assist analysis. Results: The flexural strength of mortar decreased and the compressive strength increased slowly after 28 days of exposure under low pressure and low humidity environment. Especially, the introduction of 1% NS could reduce the compressive strength loss and flexural strength loss of mortar under low pressure and low humidity environment. It was also found that the water absorption of the mortar in low pressure and low humidity environment was related to the tortuous degree of the pores inside the specimen. Conclusion: The introduction of 1% NS contributed the most to the mechanical properties (compressive strength and flexural strength) and durability (water absorption) of cement mortar.

Compressive Strength and High-Temperature Residual Strength of Cement Specimens Containing Bagasse Ash

2016 ◽  
Vol 723 ◽  
pp. 813-818
Author(s):  
I Feng Wang ◽  
Cheng Haw Lee ◽  
Chun Ku Lu
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Cement Mortar ◽  
Waste Product ◽  
High Water ◽  
Test Results ◽  
High Carbon ◽  
Cement Replacement ◽  
Binder Ratio ◽  
Water Binder Ratio

Cement is currently the most versatile and widely used material in construction. However, the high carbon emissions and energy consumption associated with the manufacture of cement remains a serious concern. bagasse ash (BA) is a secondary waste product of bagasse-fired power generation. This study investigated the use of BA as a replacement for cement as a means of reducing the environmental impact of concrete-based construction. At 28 days, we measured the water absorption of cement mortar specimens as well as the compressive strength at room-temperature and after heating. Experiments were conducted involving the replacement of various proportions of cement using BA and fly ash (FA), followed by a comparison of the physical properties. Our test results demonstrate the applicability of BA in the production of cement mortar mixtures with high water-binder ratios. It was found that the water-binder ratio determines the optimal proportion of BA when used as a replacement for cement, wherein a higher water-binder ratio means that more of the cement can be replaced with BA. In compressive strength respect, the optimal cement replacement with BA was 15 % to 25 %, whereas the optimal cement replacement with FA was 20 %. BA was shown to have a more pronounced effect in reducing water absorption in cement mortar specimens with high water-binder ratios (0.55 to 0.65). The compactness of specimens with lower water absorption enables them to retain more of their initial compressive strength following exposure to high temperatures.

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