scholarly journals Using Carbonated BOF Slag Aggregates in Alkali-Activated Concretes

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1288 ◽  
Author(s):  
Mohammad Mastali ◽  
Ahmad Alzaza ◽  
Khaled Mohammad Shaad ◽  
Paivo Kinnunen ◽  
Zahra Abdollahnejad ◽  
...  
Keyword(s):  
Drying Shrinkage ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Basic Oxygen Furnace ◽  
Pulse Velocity ◽  
Maximum Enhancement ◽  
Bof Slag ◽  
Negative Impacts ◽  
Compressive And Flexural Strengths ◽  
Alkali Activated

This experimental study aimed to develop alkali-activated concretes containing carbonated basic oxygen furnace (BOF) slag aggregates. In the first stage, the impacts of replacing normal aggregates with carbonated BOF slag aggregates in different alkali-activated concretes were determined by assessing mechanical properties (compressive and flexural strengths), morphology, thermogravimetric analyses (TGA), differential thermogravimetry (DTG) and the crystalline phases using X-ray diffraction analysis. Second, the developed plain alkali-activated concrete was reinforced by different fibre types and dosages to limit the negative impacts of the drying shrinkage and to improve strength. Therefore, the effects of using different fibre contents (1% and 1.5% in Vol.) and types (Polyvinyl alcohol [PVA], Polypropylene [PP], basalt, cellulose and indented short-length steel) on hardened state properties were evaluated. These evaluations were expressed in terms of the compressive and flexural strengths, ultrasonic pulse velocity, mass changes, drying shrinkage and efflorescence. Then, the impacts of aggressive conditions on the hardened properties of fibre-reinforced alkali-activated concretes were evaluated under carbonation, high temperature and freeze/thaw tests. The results showed that using carbonated BOF slag aggregates led to obtain higher strength than using normal aggregates in alkali activated concretes. Moreover, the maximum enhancement due to reinforcing the mixtures was recorded in alkali-activated concretes with steel fibres.

scholarly journals Production of Lightweight Alkali Activated Mortars Using Mineral Wools

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1695 ◽  
Author(s):  
Ahmad Alzaza ◽  
Mohammad Mastali ◽  
Paivo Kinnunen ◽  
Lidija Korat ◽  
Zahra Abdollahnejad ◽  
...  
Keyword(s):  
Drying Shrinkage ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Mineral Wool ◽  
Dry Density ◽  
Micro Computed Tomography ◽  
Hardened State ◽  
Compressive And Flexural Strengths ◽  
Alkali Activated

This experimental study aimed to develop a fiber-reinforced lightweight mineral wool-based alkali activated mortar. The lightweight mineral wool-based alkali activated mortars were produced using premade foam and reinforced by polypropylene (PP) fibers. They were assessed in terms of fresh and hardened-state properties. Fresh-state properties were investigated by mini-slump tests. Hardened-state characteristics were assessed by ultrasonic pulse velocity, dry density, compressive and flexural strengths, drying shrinkage, efflorescence, water absorption, and permeable porosity. For the first time, the resistance of the synthesized lightweight mineral wool-based alkali activated mortars against harsh conditions (carbonation, freeze and thaw, and high temperature) were evaluated. The porous structures of the developed lightweight alkali activated mortars were also analyzed using an X-ray micro-computed tomography (CT) technique. Lightweight mix compositions with densities in a range of 770–1510 kg/m3, compressive strengths of 1–9 MPa, and flexural strengths of 2.6–8 MPa were developed. Increases in both density and strength after carbonation were also recorded, while a decrease of strength was noticed after exposure to freeze/thaw and high temperatures of up to 500 °C.

scholarly journals Effects of a Real Exposure Class XC4 Mediterranean Climate Environment in the Behavior of Mortars Made Using Ternary Binders with Addition of Slag, Fly Ash and Limestone

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5848
Author(s):  
Javier Ibáñez-Gosálvez ◽  
Teresa Real-Herraiz ◽  
José Marcos Ortega
Keyword(s):  
Fly Ash ◽  
Mediterranean Climate ◽  
Mechanical Performance ◽  
Ultrasonic Pulse Velocity ◽  
Pore Network ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Industry ◽  
Granulated Blast Furnace Slag ◽  
Compressive And Flexural Strengths

For improving the contribution of the cement industry to mitigate global warming, many strategies have been put into practice, such as the use of eco-friendly cements with the incorporation of additions substituting clinker. Nevertheless, the use of ternary binders for the production of commercial cements is still reduced, particularly in Spain. The purpose of this research is to characterize the long-term influence produced by the exposure to a real in situ inland Mediterranean climate condition in the pore network, parameters related to durability and mechanical performance of mortars made with ternary binders, which incorporated limestone, fly ash, and ground granulated blast-furnace slag, in comparison with mortars without additions and binary blended mortars. The site verified the specifications of exposure class XC4 of Eurocode 2. The ternary and binary binders accomplished the prescriptions of cement type CEM II/B. The pore network was studied with mercury intrusion porosimetry and electrical resistivity. Water absorption, diffusion coefficient, carbonation depth, ultrasonic pulse velocity, compressive and flexural strengths have been determined. The exposure to the environment produced after 250 days an increase in porosity, a loss of pore refinement, a rise of the carbonation depths, and a reduction in the mechanical strengths, highlighting the better overall performance of ternary mortar with both fly ash and slag.

scholarly journals A Study on the Influence of Oil Palm Trunk Fiber on Ultrasonic Pulse Velocity (UPV) and Shrinkage of Foamcrete

2020 ◽  
Vol 76 (2) ◽  
pp. 111-117
Author(s):  
Md Azree Othuman Mydin ◽  
Mohd Nasrun Mohd Nawi ◽  
Muhammad Arkam Che Munaaim ◽  
Othman Mohamed
Keyword(s):  
Fracture Toughness ◽  
Oil Palm ◽  
Drying Shrinkage ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Engineering Properties ◽  
Test Results ◽  
Structural Element ◽  
Oil Palm Trunk

Presently there is increasing attention in utilization foamcrete as a lightweight non-structural and semi-structural element in buildings to take advantage of its excellent insulation properties. Though, foamcrete has been noticed to have some disadvantages: considerable brittleness; results in low compressive and flexural strength, poor fracture toughness, poor resistance to crack propagation and low impact strength. Hence this study is intended to look into the potential of oil palm trunk (OPT) fiber in enhancing the engineering properties of foamcrete. There are 2 engineering properties will be focused in this study which are ultrasonic pulse velocity and drying shrinkage. Two densities of foamcrete of 600 kg/m3, 1200 kg/m3 were cast and tested. The ratio of cement, sand and water used in this study was 1:1.5:0.45. OPT fibers were used as additives at 0.15%, 0.30%, 0.45% and 0.60% by volume of the total mix. Test results indicated that the engineering properties of foamcrete reinforced with OPT fiber had amplified thoroughly.

scholarly journals Effect of alkali content and slag content on the fresh and hardened properties of air-cured alkali activated mortar containing fly ash

2021 ◽  
Author(s):  
Thushara Raju ◽  
Namitha S ◽  
Muhammed Nabil K ◽  
Mohammed Rafeeque N. V ◽  
Reshma Sundhar ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Construction Material ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Alkali Content ◽  
Hardened Properties ◽  
Alkali Activated ◽  
Slag Content

Alkali Activated Material (AAM) is introduced as a pioneering construction material in the construction diligence to trim down the utilization of Ordinary Portland Cement (OPC) and to curtail the amount of carbon dioxide released during the production of OPC. Modestly refined industrial by products or natural materials rich in alumino silicates are the binding agents used in AAM. Generally, heat curing is needed for the alkali activated mortar to achieve the required hardened properties and this difficulty can be overcome by adding slag to the mix. In this experimental analysis, the alkali activated mortar mixes with different proportions of glassy granulated slag and Class F fly ash were prepared without the usage of superplasticizers, with alkali to binder (a/b) ratios of 0.7, 0.8 and 0.9. The rheological characteristics of mortar were studied using flow table apparatus and hardened properties were studied using compressive strength test and ultrasonic pulse velocity (UPV) test by testing cylindrical specimens of size 25 mm diameter and 50 mm height. The mortar specimens were air-cured, and the compressive strength and UPV test were conducted after 3 and 7 days. The test results showed that due to the presence of higher alkali content and the decrease in slag content, the workability of alkali activated mortar was improved, but the measure of strength decreased. The mix with 100% slag and a/b ratio of 0.8 had the best UPV value, indicating its quality among the various mortar mixes studied. This study portrays the significance of optimising the alkali and slag content in tailor making an alkali activated mortar system with good hardened properties.

scholarly journals Characteristics of Preplaced Aggregate Concrete Fabricated with Alkali-Activated Slag/Fly Ash Cements

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 591
Author(s):  
Salman Siddique ◽  
Hyeju Kim ◽  
Hyemin Son ◽  
Jeong Gook Jang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Grout ◽  
Aggregate Concrete ◽  
Alkali Activated ◽  
Alkali Activated Cement

This study assesses the characteristics of preplaced aggregate concrete prepared with alkali-activated cement grout as an adhesive binder. Various binary blends of slag and fly ash without fine aggregate as a filler material were considered along with different solution-to-solid ratios. The properties of fresh and hardened grout along with the properties of hardened preplaced concrete were investigated, as were the compressive strength, ultrasonic pulse velocity, density, water absorption and total voids of the preplaced concrete. The results indicated that alkali-activated cement grout has better flowability characteristics and compressive strength than conventional cement grout. As a result, the mechanical performance of the preplaced aggregate concrete was significantly improved. The results pertaining to the water absorption and porosity revealed that the alkali-activated preplaced aggregate concrete is more resistant to water permeation. The filling capacity based on the ultrasonic pulse velocity value is discussed to comment on the wrapping ability of alkali-activated cement grout.

scholarly journals STATE OF THE ART OF TANK STRUCTURAL EVALUATION REVIEW: A CASE STUDY OF AN ELEVATED CONCRETE WATER TANK CONCERNING CRACK INITIATION

2021 ◽  
Vol 56 (5) ◽  
pp. 90-106
Author(s):  
Taufiq Rochman ◽  
Suhariyanto
Keyword(s):  
Crack Initiation ◽  
Crack Width ◽  
Drying Shrinkage ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Water Tank ◽  
Structural Evaluation ◽  
Floor Slabs

This study aims at the structural evaluation of the elevated concrete water tank condition, including crack initiation, through nondestructive testing. The growing demands for environmental quality have resulted in a rise in the design and construction of tanks and reservoirs in the construction industry. Cracks for water line leakage were found during watertight testing in concrete tanks. Long-term liquid leaking may permanently damage the tank and can contaminate the groundwater. Given the critical existence of leaked cracks in tank serviceability and durability, the contribution examines the triggers and effects of their occurrence. An inspection of the existing water tank system is conducted to ascertain its condition. The investigation included structural design checks, concrete compressive strength tests, visual assessments, hammer inspections, and Ultrasonic Pulse Velocity (UPV) testing with Portable Ultrasonic Non-Destructive Digital Indicating Tester (PUNDIT). This observation is made at many elevations on various sampling points on the tank structure's elements, including columns, beams, tank floor slabs, and tank wall shells. The results indicate the presence of flexural type cracks in the main beam's middle span and diagonal beams. Additionally, cracks attributed to long-term drying shrinkage were discovered on the diagonal of the floor slab and cracks of the same pattern on the main beam's middle span. The deflection estimated by structural remodeling was larger than the deflection estimated by design. The computed crack width in the main and diagonal beam exceeds the acceptable crack width.

scholarly journals INVESTIGATION THE EFFECTS OF GREEN MORTAR PARAMETERS USING ANALYTICAL METHODS

2021 ◽  
pp. 1-17
Author(s):  
Eethar Dawood ◽  
Mafaz Abdullah
Keyword(s):  
Regression Analysis ◽  
Ecological Impact ◽  
Steel Slag ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Flow Density ◽  
Second Phase ◽  
Waste Glass Powder ◽  
Compressive And Flexural Strengths

The various green mortar mixes have been used in this study using various percentages of waste glass powder (WGP), steel slag (SG) and Micro-silica fume(SF).The different properties of flow, density, ultrasonic pulse velocity (UPV), compressive and flexural strengths have been tested for such green mortar in the  first phase of experimental work. The second phase deals with the regression analysis of such properties. Whereas, the analysis of the results have also been using the integrated AHP and TOPSIS methods for selection the best performance of the green mortar due to the ecological effects of such materials. The results showed that the use of 70%OPC+8%WGP+12%SG+10% SF indicated as the best performance in term of ecological impact compared with other mortar mixes. Also, the regression analysis using the integrated AHP and TOPSIS methods gives an effective strategy for the selection of the best mortar mix.

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