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.

Improved Acid Rain Resistance of High Calcium Fly Ash-sodium Hydroxide Geopolymer Mortar Cured at Ambient Temperature by Incorporating Rice Husk Ash

2021 ◽  
Vol 47 (2) ◽  
pp. 324-331
Author(s):  
Prinya Chindaprasirt ◽  
Kiatsuda Somna
Keyword(s):  
Compressive Strength ◽  
Sulfuric Acid ◽  
Fly Ash ◽  
Nitric Acid ◽  
Acid Rain ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Acid Resistance ◽  
Portland Cement Concrete ◽  
High Calcium

Geopolymer is an aluminosilicate material, synthesized from source materials rich in silica and alumina and alkali solution. This product provides similar strength to Portland cement concrete. Geopolymer exhibits a wide variety of properties and characteristics, including high compressive strength, low shrinkage, acid resistance, fire resistance and low thermal conductivity. In term of acid resistance, acid rain is an important consideration due to global warming. Structures deteriorate as a result of persistence contact with acid rain with of pH less than 5. Thus, this research aims to improve acid resistance of fly ash-NaOH geopolymer mortars by incorporating rice husk ash (RHA). Artificial acid rain solution was prepared by mixing nitric acid and sulfuric acid at the ratio of 70:30 v/v. The geopolymer mortars were immersed in 5% nitric acid, 5% sulfuric acid, and 5% synthetic acid rain solutions for 36 weeks. The evaluations of its resistance to acid solution was investigated with surface corrosion, compressive strength, and microstructure. The results showed that the incorporation of RHA improved the acid rain resistance of geopolymer mortar through pore refinement and increase in strength. The mortar with fly ash to RHA ratio of 90:10 provided the highest compressive strength and good resistance to acid rain.

scholarly journals Effects of Sand Powder on Sulfuric Acid Resistance, Compressive Strength, Cost Benefits, and CO2 Reduction of High CaO Fly Ash Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Surachet Wanna ◽  
Warangkana Saengsoy ◽  
Pisanu Toochinda ◽  
Somnuk Tangtermsirikul
Keyword(s):  
Compressive Strength ◽  
Sulfuric Acid ◽  
Fly Ash ◽  
Co2 Emission ◽  
Carbon Dioxide Emission ◽  
Co2 Reduction ◽  
Acid Resistance ◽  
Economic Benefits ◽  
Strength Development ◽  
Compressive Strength Development

This article studies the efficiency of sand powder as a supplementary cementitious material (SCM) in improving the sulfuric acid resistance of concrete incorporated with high CaO fly ash. Besides, the effects of sand powder on compressive strength development, mitigation of carbon dioxide emission, and cost-effectiveness are addressed. Paste mixtures with W/B ratios of 0.25 and 0.40 were used in this study for the performances of sulfuric acid resistance and long-term compressive strength development. The test results indicated that sand powder could reduce the weight loss of the tested paste specimens in sulfuric acid solution with a pH of 1, compared to the control specimens, especially for the specimens incorporated with high CaO fly ash. The sand powder addition could also increase the compressive strength of cement pastes at the age of 90 days by 26.27% and 43.80% for W/B ratios of 0.25 and 0.40, respectively. The use of sand powder in the evaluated concrete mixture could also reduce CO2 emission by 23.23% and lower the cost of the mixtures by 8.05%, compared to the control mixture. The addition of sand powder could significantly increase the sulfuric acid resistance, compressive strength, and economic benefits and reduce the CO2 emission of high CaO fly ash-cement-based materials.

Durability of Fly Ash Geopolymer Mortars in Corrosive Environments, Compared to that of Cement Mortars

2014 ◽  
Vol 92 ◽  
pp. 84-89 ◽  
Author(s):  
A. Asprogerakas ◽  
Aristea Koutelia ◽  
Glykeria Kakali ◽  
Sotirios Tsivilis
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Building Materials ◽  
Acid Resistance ◽  
Chloride Diffusion ◽  
Strength Development ◽  
Acid Attack ◽  
Calcareous Sand ◽  
Cement Mortars ◽  
Improved Performance

In the present paper the durability of fly ash geopolymer mortars compared to that of cement mortars is investigated. Geopolymers can improve the ecological image of building materials, especially when their production is based on industrial by-products such as fly ash. Three series of fly ash based geopolymer mortars were prepared using calcareous sand to fly ash ratio (S/FA) varying from 0.5 to 2. In addition, cement mortar specimens were prepared using cement CEM I 42.5 N and CEM II 32.5 N. Durability of geopolymer and cement mortars was evaluated by means of compressive strength development, acid resistance, chloride diffusion and sulfate resistance. It was found that fly ash can be effectively used to produce geopolymer mortars with calcareous sand. Geopolymers exhibit competitive compressive strength compared to that of cement mortars. Geopolymer mortars develop their maximum compressive strength a few days after their casting. Geopolymer and cement mortars exhibit satisfactory resistance to sulphate attack. Cement mortars, generally, show better behaviour (compared to geopolymers) in chloride diffusion. Finally, geopolymers indicate improved performance against acid attack, compared to that of cement mortars.

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 Corrosion Inhibitory Effects of Mullite in Concrete Exposed to Sulfuric Acid Attack

2020 ◽  
Vol 1 (2) ◽  
pp. 282-295
Author(s):  
Shima Taheri ◽  
Gerardo Pareja Delgado ◽  
Oluwatoosin B. A. Agbaje ◽  
Paritosh Giri ◽  
Simon Martin Clark
Keyword(s):  
Sulfuric Acid ◽  
Prolonged Exposure ◽  
Acid Corrosion ◽  
Hardness Test ◽  
Aluminum Silicate ◽  
Acid Attack ◽  
Concrete Pipes ◽  
Physicochemical Changes ◽  
Sulfuric Acid Solutions

Prolonged exposure to low pH conditions affects the durability of concrete. In this work, the effect of mullite, aluminum silicate, on the strength and the acid corrosion of mortar and concrete under induced accelerated conditions in sulfuric acid solutions at pH of 0.25 and 1 was studied. The characterization of physicochemical changes was performed using techniques including compressive strength, scanning electron microscopy, micro-X-ray fluorescence spectrometry, and the Vickers hardness test. The results indicate that the addition of mullite does not have any significant effect on the overall strength of mortar and concrete samples, while it significantly increases their resistance to corrosion caused by sulfate attack by 90%, therefore, it is expected to increase the life span and decrease the maintenance costs of concrete pipes subjected to acid corrosion in sewer environments. The inhibition efficiency is observed to be sensitive to acid concentration and was improved with increase in the amount of mullite in samples.

scholarly journals Effects of Oil Palm Shell Coarse Aggregate Species on High Strength Lightweight Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Ming Kun Yew ◽  
Hilmi Bin Mahmud ◽  
Bee Chin Ang ◽  
Ming Chian Yew
Keyword(s):  
Compressive Strength ◽  
Oil Palm ◽  
Lightweight Concrete ◽  
Good Condition ◽  
High Strength ◽  
Pulse Velocity ◽  
Dry Density ◽  
Coarse Aggregates ◽  
Palm Shell ◽  
Oil Palm Shell

The objective of this study was to investigate the effects of different species of oil palm shell (OPS) coarse aggregates on the properties of high strength lightweight concrete (HSLWC). Original and crushed OPS coarse aggregates of different species and age categories were investigated in this study. The research focused on two OPS species (duraandtenera), in which the coarse aggregates were taken from oil palm trees of the following age categories (3–5, 6–9, and 10–15 years old). The results showed that the workability and dry density of the oil palm shell concrete (OPSC) increase with an increase in age category of OPS species. The compressive strength of specimen CD3 increases significantly compared to specimen CT3 by 21.8%. The maximum achievable 28-day and 90-day compressive strength is 54 and 56 MPa, respectively, which is within the range for 10–15-year-old crushedduraOPS. The water absorption was determined to be within the range for good concrete for the different species of OPSC. In addition, the ultrasonic pulse velocity (UPV) results showed that the OPS HSLWC attain good condition at the age of 3 days.

Influence of Foaming Agent on the Properties of High Density Foam Concrete

2011 ◽  
Vol 399-401 ◽  
pp. 1214-1217 ◽  
Author(s):  
Xin Gang Yu ◽  
Yan Na Gao ◽  
Lin Lin ◽  
Fang Li
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Lightweight Concrete ◽  
Drying Shrinkage ◽  
High Strength ◽  
High Density ◽  
Low Density ◽  
Dilution Ratio ◽  
Foam Concrete ◽  
Foaming Agent

Lightweight concrete has been used for structural purposes for many years and it is developed very fast in resent years due to its lightweight and favourable for insulation properties. High strength foam concrete is a fairly new kind of lightweight concrete with excellent properties of outstanding workability, low density and high strength. Responsible for these properties are the macro-, meso- and micro- porosity of the foam concrete which are mainly affected by the foaming agent. The influence of foaming agent’s dilution ratio and foam dosage on the fluidity, compressive strength, flexural strength and drying shrinkage of high density foam concrete designed for structural materials is investigated in this paper.

scholarly journals Effect of Curing Temperature Histories on the Compressive Strength Development of High-Strength Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Keun-Hyeok Yang ◽  
Jae-Sung Mun ◽  
Myung-Sug Cho
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Relative Strength ◽  
Curing Temperature ◽  
Strength Development ◽  
Curing Conditions ◽  
Strength Concrete ◽  
Equivalent Age ◽  
Compressive Strength Development

This study examined the relative strength-maturity relationship of high-strength concrete (HSC) specifically developed for nuclear facility structures while considering the economic efficiency and durability of the concrete. Two types of mixture proportions with water-to-binder ratios of 0.4 and 0.28 were tested under different temperature histories including (1) isothermal curing conditions of 5°C, 20°C, and 40°C and (2) terraced temperature histories of 20°C for an initial age of individual 1, 3, or 7 days and a constant temperature of 5°C for the subsequent ages. On the basis of the test results, the traditional maturity function of an equivalent age was modified to consider the offset maturity and the insignificance of subsequent curing temperature after an age of 3 days on later strength of concrete. To determine the key parameters in the maturity function, the setting behavior, apparent activation energy, and rate constant of the prepared mixtures were also measured. This study reveals that the compressive strength development of HSC cured at the reference temperature for an early age of 3 days is insignificantly affected by the subsequent curing temperature histories. The proposed maturity approach with the modified equivalent age accurately predicts the strength development of HSC.

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