scholarly journals Exposing Sustainable Mortars with Nanosilica, Zinc Stearate, and Ethyl Silicate Coating to Sulfuric Acid Attack

2018 ◽  
Vol 10 (10) ◽  
pp. 3769 ◽  
Author(s):  
Victoria García-Vera ◽  
Antonio Tenza-Abril ◽  
Marcos Lanzón ◽  
José Saval
Keyword(s):  
Compressive Strength ◽  
Sulfuric Acid ◽  
Mass Loss ◽  
Water Absorption ◽  
Zinc Stearate ◽  
Acid Exposure ◽  
Ethyl Silicate ◽  
Acid Attack ◽  
Water Absorption Coefficient ◽  
Silicate Coating

Obtaining durable materials that lengthen the service life of constructions and thereby contribute to sustainability requires research into products that improve the durability of cementitious materials under aggressive conditions. This paper studies the effects of sulfuric acid exposure on four mortar types (control mortar, mortar with nanosilica, mortar with zinc stearate, and mortar with an ethyl silicate coating), and evaluates which of them have better performance against the acid attack. After 28 days of curing, the samples were exposed to a sulfuric acid attack by immersing them in a 3% w/w of H2SO4 solution. Physical changes (mass loss, ultrasonic pulse velocity, open porosity, and water absorption), and mechanical changes (compressive strength) were determined after the sulfuric acid exposure. A scanning electron microscope (SEM) was used to characterize the morphology of the surface mortars after the exposure. The control mortar had the highest compressive strength after the acid attack, although of the four types, the zinc stearate mortar showed the lowest percentage of strength loss. The zinc stearate mortar had the lowest mass loss after the acid exposure; moreover, it had the lowest capillary water absorption coefficient (demonstrating its hydrophobic effect) both in a non-aggressive environment and acid attack.

scholarly journals Effect of Magnetized Water on the Mechanical and Durability Properties of Concrete Block Pavers

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1647 ◽  
Author(s):  
Saeid Ghorbani ◽  
Mostafa Gholizadeh ◽  
Jorge de Brito
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Sulfuric Acid ◽  
Flexural Strength ◽  
Water Absorption ◽  
Concrete Block ◽  
Splitting Tensile Strength ◽  
Acid Attack ◽  
Magnetized Water ◽  
Positive Effect

In this research, the effect of magnetized water on the mechanical and durability behavior of concrete block pavers was investigated. For this purpose, a total of five mixes were prepared with water that passed through a permanent magnetic field 10, 20, 40, and 80 times at a constant speed of 2.25 m/s. Compressive strength, splitting tensile strength, flexural strength, resistance to sulfuric acid attack, water absorption tests, and Scanning Electron Microscopy (SEM) analyses were conducted. The compressive strength, splitting tensile strength, and flexural strength test results showed a significant positive effect of using magnetized water. The remaining tests also revealed that using magnetized water increases the resistance of concrete block pavers to sulfuric acid attack and decreases their water absorption.

scholarly journals Water Absorption Properties of Geopolymer Foam after Being Impregnated with Hydrophobic Agents

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4162
Author(s):  
Hiep Le Chi ◽  
Pavlína Hájková ◽  
Su Le Van ◽  
Petr Louda ◽  
Lukáš Voleský
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Positive Impact ◽  
High Sensitivity ◽  
Acoustic Properties ◽  
Total Water ◽  
Absorption Properties ◽  
Major Barrier ◽  
Water Absorption Coefficient ◽  
Hydrophobic Agent

Geopolymer foam is classified as a lightweight material with high porous in its matrix which has great offer for applications requiring fire-resistant, thermal, and acoustic properties. However, the high sensitivity to humid environments can be a major barrier of geopolymer foam that limits the variety of applications of this material. Based on this drawback, two types of hydrophobic agent (Lukosil M130 and Lukofob ELX) were used as an impregnator to treat the surface of geopolymer foam samples. This paper presented the results of water absorption properties of the untreated and treated geopolymer foam composites. The obtained properties were flexural strength, compressive strength, density, total water absorption, the rate of water absorption, and water absorption coefficient. The results showed that the samples after being impregnated with hydrophobic agents improved significantly their waterproof property especially using Lukosil M130. Moreover, the samples treated with Lukosil M130 had positive impact on their mechanical strength.

scholarly journals Pore Structure Degradation of Different Cement Mortars Exposed to Sulphuric Acid

2019 ◽  
Vol 9 (24) ◽  
pp. 5297 ◽  
Author(s):  
José Ortega ◽  
Victoria García-Vera ◽  
Afonso Solak ◽  
Antonio Tenza-Abril
Keyword(s):  
Compressive Strength ◽  
Sulphuric Acid ◽  
Construction Material ◽  
Zinc Stearate ◽  
Acid Attack ◽  
Structure Degradation ◽  
Refined Microstructure ◽  
Cement Mortars ◽  
Different Types ◽  
Pronounced Reduction

Acid attack causes the deterioration of construction material surfaces. The objective of this study was to investigate the degradation of different types of cement mortar in terms of variations in pore size distribution obtained by mercury intrusion porosimetry (MIP), mass loss, and compressive strength. The mortars were manufactured with nanosilica, zinc stearate, and an ethyl silicate coating. After curing (28 days), the samples were subjected to acid exposure for 90 days, immersed ina solution (3% w/w) of sulphuric acid (H2SO4). The results indicate that the mortars showed a more refined microstructure, with a higher proportion of smaller pores (<100 nm) compared to the control mortar. The 28-day and 90-day compressive strength variations of mortars were also determined by observing pronounced reduction due to the appearance of expansive compounds responsible for microcracking.

scholarly journals BRIEF EVALUATION OF MASS LOSS INDEX, WATER ABSORPTION AND COMPRESSIVE STRENGTH REVERTIBILITY COEFFICIENTS OF PAPERBRICKS IMMERSED IN WATER

2015 ◽  
pp. 24-30
Author(s):  
Akinwande Abayomi
Keyword(s):  
Weight Loss ◽  
Compressive Strength ◽  
Mass Loss ◽  
Water Absorption ◽  
Cement Content ◽  
Sand Content ◽  
Loss Index

With the need to develop alternative, lightweight cheaper bricks for masonry which will be durable, paperbrick produced with varying cement content of 3 – 18 wt. % and fixed sand content of 20 wt. % were immersed in water for seven days, it was observed that with increasing cement content and curing ages, compressive strength revertibility increased. Weight loss index also reduced with higher cement content and longer curing days and concluded that higher cement content and longer duration periods produce more water durable paperbricks.

scholarly journals Influence of Crystalline Admixtures on the Short-Term Behaviour of Mortars Exposed to Sulphuric Acid

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 82 ◽  
Author(s):  
Victoria García-Vera ◽  
Antonio Tenza-Abril ◽  
José Saval ◽  
Marcos Lanzón
Keyword(s):  
Compressive Strength ◽  
Absorption Coefficient ◽  
Water Absorption ◽  
Sulphuric Acid ◽  
Cementitious Materials ◽  
Pulse Velocity ◽  
Capillary Water ◽  
Short Term ◽  
Water Absorption Coefficient ◽  
Capillary Water Absorption

Using durable materials is a sustainable solution for extending the lifetime of constructions. The use of crystalline admixtures makes cementitious materials more durable. They plug pores, capillary tracts and microcracks, blocking the entrance of water due to the formation of crystals that prevent the penetration of liquids. The literature has covered the performance of these admixtures on concrete, but studies on mortars are still scarce. The aim of this study is to investigate the effect of an aggressive environment (sulphuric acid solution—3 wt%) on mortars produced with different percentages of a crystalline admixture (1%, 1.5% and 2% by weight of cement content). Physical and mechanical properties were studied after immersing the mortars in a H2SO4 solution for 90 days. It was found that, after a 90-day sulphuric acid exposure, mortars with the crystalline admixture showed greater compressive strength than the control mortar, besides exhibiting lower mass loss. However, the crystalline admixture did not produce any significant effect on the capillary water absorption coefficient. In a nonaggressive environment, and in the short term, the crystalline admixture did not have a significant effect on the compressive strength, the capillary water absorption coefficient or the ultrasonic pulse velocity.

EFFECT OF SULPHURIC ACID ON CONCRETE WITH IRON ORE TAILINGSc

2016 ◽  
Vol 78 (6-12) ◽  
Author(s):  
Ali Umara Shettima ◽  
Mohd Warid Hussin ◽  
Yusof Ahmad ◽  
Mohammed Yau
Keyword(s):  
Compressive Strength ◽  
Mass Loss ◽  
Sulphuric Acid ◽  
Iron Ore ◽  
Strength Loss ◽  
Test Results ◽  
X Ray Diffraction ◽  
Acid Attack ◽  
Failure Patterns ◽  
Iron Ore Tailings

Researches into the uses of waste materials are increasingly being explored to meet up society’s needs and global protection for sustainable, safe and economic development. This paper assessed concrete with iron ore tailings (IOT) exposed to dilute sulphuric acid. Iron ore tailings are the materials left-over after separating the valuable fraction from the uneconomic fraction of an ore. To study the effect of sulphuric acid, concrete of 100 mm cube with a different mix ratios containing IOT were prepared and cured for 28 days in water. The cubes were later immersed into dilute sulphuric acid at a concentration of 5%. The compressive strength of concrete at 7, 28 and 90 days of water curing were determined. Mass loss and strength reduction due to sulphuric effect were evaluated at 7, 28 and 90 days respectively. XRD microstructure of concrete specimens was analysed. Test results indicated that the IOT could be used in concrete as sand replacement since the concrete with IOT has similar trend in compressive strength loss and mass loss to sulphuric acid attack compared to control specimen. The mineralogical crystal failure patterns due to the sulphuric acid in terms X-ray diffraction analysis are the same for control and IOT concrete. 

scholarly journals Severe Sulfuric Acid Attack on Self-Compacting Concrete with Granulometrically Optimized Blast-Furnace Slag-Comparison of Different Test Methods

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1431
Author(s):  
Sara Irico ◽  
Laurence De Meyst ◽  
Dirk Qvaeschning ◽  
Maria Cruz Alonso ◽  
Kristina Villar ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Sulfuric Acid ◽  
Mass Loss ◽  
Blast Furnace Slag ◽  
Moderate Increase ◽  
Acid Attack ◽  
Slag Cement ◽  
Self Compacting Concrete ◽  
Acid Media ◽  
Furnace Slag

The corrosion by severe sulfuric acid attack at pH 2 of two self-compacting concrete (SCC) types that are based on ordinary Portland cement (OPC) and granulometrically optimized blast-furnace slag cement was evaluated by three complementary tests that were performed in different research institutes. The use of SCC is a smart and promising solution to improve the performance of concrete in an aggressive environment, especially regarding ready-mixed concrete applications, since good compaction is less dependent on workmanship. The relevance and practical advantages of the different test protocols and the influence of the experimental parameters are discussed. It appears that the frequency of renewing the acid solution during the exposure period is the main parameter that influences the mass loss and the rate of degradation, while the sample geometry and the ratio between the volume of solution and concrete surface area had no clear influence. Nevertheless, there was reasonable agreement between the methods regarding the magnitude of the concrete degradation (resulting in a mass loss of about 2.5 kg/m² in six months time). The use of granulometrically optimized slag cement provided a moderate increase of the concrete resistance against acid attack, and this practice might be recommended in order to increase the durability of structures exposed to sulfuric acid media. The fact that the difference in comparison with SCC-OPC was rather limited shows that the influence of the cement type becomes less relevant in the case of concrete with low w/c ratio and optimized concrete technology.

scholarly journals The effect of pozzolanic mineral additives on the strength and durability properties of structural lightweight concrete

2021 ◽  
Vol 2 (2) ◽  
pp. 35-40
Author(s):  
Engin Yener
Keyword(s):  
Compressive Strength ◽  
Sulfuric Acid ◽  
Nitric Acid ◽  
Lightweight Concrete ◽  
Acid Resistance ◽  
High Strength ◽  
Strength Development ◽  
Acid Attack ◽  
Ductile Behavior ◽  
Sulfuric Acid Solutions

Structural lightweight concretes have the potential to be used in road pavements and bridge decks due to their properties such as sufficient wear resistance, high impermeability, superior freeze-thaw resistance and ductile behavior. However, road pavements are directly exposed to nitric acid and sulfuric acid solutions created by the exhaust gases of transportation vehicles in humid environments. Therefore, the concrete to be used in road pavements must be resistant to these acid effects. In addition, sufficient strength must be guaranteed when used as pavement material. The aim of this study is to produce lightweight concrete suitable for road pavements and other structures exposed to acid effects. For this, the effect of silica fume (SF) and fly ash (FA) on acid resistance and strength development of lightweight concrete with perlite aggregates was investigated. Five different lightweight concrete mixtures were produced by substituting 0%, 5%SF, 10% SF, 10%FA, 20% FA instead of cement by weight. Natural perlite rock has been used as an aggregate source in order to provide high strength and lightness. The cylindrical samples produced were kept in lime saturated water cure for 120 days and their compressive strength was measured on the 28th, 56th, 90th and 120th days. In addition, in order to monitor the acid resistance, the strength changes of the samples exposed to 5% sulfuric acid and 5% nitric acid solution after 28 days of standard curing were followed until the 120th day. Results show that, SF and FA additives increase the compressive strength especially at older ages. In case of 10% SF, the 120-day strength value increased by 18.6% and reached 34.5 MPa. Also, lightweight perlite concrete is highly resistant to nitric acid and sulfuric acid effects. In the case of 92 days of nitric acid and sulfuric acid exposure, the strength losses are only 5.2% and 13.4%, respectively. In order to fully benefit from SF and FA, concretes must be adequately cured before acid attack. It has been concluded that it is possible to produce high-strength and acid-resistant lightweight concretes suitable for road pavements and many other structural elements by using natural perlite aggregate.

scholarly journals Performance and Micro Structural Analysis of Portland Slag Cement Mortar Induced with Pozzolanic Additives

2019 ◽  
Vol 8 (4) ◽  
pp. 744-750
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Structural Analysis ◽  
Water Absorption ◽  
Cement Mortar ◽  
Partial Replacement ◽  
Acid Attack ◽  
Slag Cement ◽  
Split Tensile Strength ◽  
Portland Slag Cement

Portland cement is a kind of cement used where the high strength and durability is needed. Also, this type of cement is essentially used to control the CO2 emission during the manufacturing process of the concrete. This cement is made up of slag with the activator such as alkalis in the form of sodium hydroxide or sodium silicate. However, this addition is increasing the overall cost of the production of concrete. In this research, a new attempt has been made to use the natural activators of Rice Husk Ash (RHA) and Natural Steatite Powder (NSP). This research aims to determine the effects of RHA and NSP with Portland slag cement by partial replacement with 5%, 10%, 15% and 20% of RHA and NSP. The influence of the RHA and NSP on the mechanical properties of the mortar was evaluated by measuring the compressive strength and the split tensile strength. The durability properties of the specimens were analyzed by water absorption, sorpitivity and acid attack tests. The analysis of the microstructure of the specimens was done by scanning electron microscope (SEM) and Fourier Transform Infrared Spectra analysis (FTIR). It was observed that the maximum compressive strength and split tensile strength was in 5% RHA and NSP blended mortar. The durability results showed that the 10% RHA and 10% NSP had lesser water absorption and sorpitivity values. From the results of micro structural analysis it was observed that replacing cement with 5% RHA and 5% NSP results in improvement of microstructure of cement mortar.

scholarly journals Durability Performance of Self-Compacting Concrete Containing Crumb Rubber, Fly Ash and Calcium Carbide Waste

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 488
Author(s):  
Sylvia Kelechi ◽  
Musa Adamu ◽  
Abubakar Mohammed ◽  
Yasser Ibrahim ◽  
Ifeyinwa Obianyo
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Calcium Carbide ◽  
Crumb Rubber ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Acid Attack ◽  
Self Compacting Concrete ◽  
Durability Properties

Waste tire disposal continues to pose a threat to the environment due to its non-biodegradable nature. Therefore, some means of managing waste tires include grinding them to crumb rubber (CR) sizes and using them as a partial replacement to fine aggregate in concrete. However, the use of CR has a series of advantages, but its major disadvantage is strength reduction. This leads to the utilization of calcium carbide waste (CCW) to mitigate the negative effect of CR in self-compacting concrete (SCC). This study investigates the durability properties of SCC containing CR modified using fly ash and CCW. The durability properties considered are water absorption, acid attack, salt resistance, and elevated temperature of the mixes. The experiment was conducted for mixes with no-fly ash content and their replica mixes containing fly ash to replace 40% of the cement. In the mixes, CR was used to partially replace fine aggregate in proportions of 0%, 10%, and 20% by volume, and CCW was used as a partial replacement to cement at 0%, 5%, and 10% by volume. The results indicate that the mixes containing fly ash had higher resistance to acid (H2SO4) and salt (MgSO4), with up to 23% resistance observed when compared to the mix containing no fly ash. In addition, resistance to acid attack decreased with the increase in the replacement of fine aggregate with CR. The same principle applied to the salt attack scenario, although the rate was more rapid with the acid than the salt. The results obtained from heating indicate that the weight loss was reduced slightly with the increase in CCW, and was increased with the increase in CR and temperature. Similarly, the compressive strength was observed to slightly increase at room temperature (27 °C) and the greatest loss in compressive strength was observed between the temperature of 300 and 400 °C. However, highest water absorption, of 2.83%, was observed in the mix containing 20% CR, and 0% CCW, while the lowest water absorption, of 1.68%, was found in the mix with 0% CR, 40% fly ash, and 10% CCW. In conclusion, fly ash is recommended for concrete structures immersed in water, acid, or salt in sulphate- and magnesium-prone areas; conversely, fly ash and CR reduce the resistance of SCC to heat beyond 200 °C.

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