scholarly journals Properties of a Lightweight Fly Ash–Slag Alkali-Activated Concrete with Three Strength Grades

2021 ◽  
Vol 11 (2) ◽  
pp. 766
Author(s):  
Huailiang Wang ◽  
Yuhui Wu ◽  
Lang Wang ◽  
Huihua Chen ◽  
Baoquan Cheng
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Fracture Energy ◽  
Lightweight Concrete ◽  
Pulse Velocity ◽  
Normal Weight ◽  
Splitting Tensile Strength ◽  
Alkali Activated Concrete ◽  
Alkali Activated

Lightweight alkali-activated concrete (LAAC) is a type of highly environmentally friendly concrete, which can provide the benefits of both alkali-activated material and lightweight concrete. The study aimed to investigate the influence of different water/solid (W/S) ratios on the properties of normal-weight/lightweight fly ash–slag alkali-activated concrete manufactured at ambient temperature. The relative performance of the alkali-activated concrete (AAC) mixes with limestone and sintered fly ash lightweight aggregates as the coarse aggregates was also compared to the conventional ordinary Portland cement (OPC) concrete mix in terms of their compressive stress–strain relationship, splitting tensile strength and fracture parameters. The morphologies and microstructure of the four types of interfacial transition zones (ITZs) were characterized by scanning electron microscopy (SEM). Results indicated that the AAC had a higher tensile strength, stress intensity factor, brittleness and lower elastic modulus than its cement counterpart. With the decrease in the W/S ratio, the density, compressive and tensile strength, ultrasonic pulse velocity, fracture energy, brittleness and elastic modulus of the AAC increase. However, the influence of the W/S ratio on the mechanical properties of the LAAC with lightweight porous aggregates was less than that of the normal-weight AAC. Predictive models of the splitting tensile strength, fracture energy and elastic modulus of the AAC were also suggested, which were similar to those of the OPC concrete. Furthermore, the microstructure investigation showed that no wall effect occurred in the ITZ of the AAC. The ITZ structure of the hardened AAC was also more compact and uniform than that of the OPC concrete.

scholarly journals Selected Strength Properties of Coal Bottom Ash (CBA) Concrete Containing Fly Ash under Different Curing and Drying Conditions

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5381
Author(s):  
Ji-Hun Park ◽  
Quang-The Bui ◽  
Sang-Hwa Jung ◽  
In-Hwan Yang
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Bottom Ash ◽  
Ultrasonic Pulse Velocity ◽  
Strength Properties ◽  
Pulse Velocity ◽  
Splitting Tensile Strength ◽  
Fine Aggregates ◽  
Drying Conditions

This study aims to evaluate the effect of curing and drying conditions on the strength properties of concrete containing coal bottom ash (CBA) and fly ash as substitutes for fine aggregates and cement, respectively. The strength properties of the concrete including CBA and fly ash were evaluated under two different curing and drying conditions: saturated surface-dry (SSD) conditions and oven-dried conditions at curing ages of 28 and 91 days. The natural fine aggregates of the mixtures were replaced by CBA fine aggregates at 25%, 50%, 75%, and 100% by volume. In addition, the cement in the mixtures was partly replaced with fly ash at 20% and 40%. The experimental program included the measurement of the unit weight, compressive strength, splitting tensile strength, flexural strength, and ultrasonic pulse velocity of the concrete. The test results showed that the compressive strength, splitting tensile strength, and flexural strength decreased as the CBA content increased under both SSD and oven-dried conditions. The curing and drying conditions of the concrete with CBA and fly ash considerably influenced the reduction in the compressive, splitting, and flexural tensile strengths of the concrete. Additionally, the experimental results showed that fly ash insignificantly contributed to the reduction in the strength properties under both SSD and oven-dried conditions. Finally, the relationships between ultrasonic pulse velocity and the splitting tensile strength, flexural tensile strength, and compressive strength were investigated.

scholarly journals Experimental Study of the Dynamic Compressive and Tensile Strengths of Fly Ash and Slag Based Alkali-Activated Concrete Reinforced With Basalt Fibers

2021 ◽  
Vol 8 ◽  
Author(s):  
Chong Lian ◽  
Yubo Wang ◽  
Shan Liu ◽  
Yifei Hao
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Strain Rate ◽  
Dynamic Strength ◽  
Test Results ◽  
Complete Replacement ◽  
Alkali Activated Concrete ◽  
Alkali Activated

The use of industrial by-products, e.g., fly ash, slag, as complete replacement of Portland cement to make alkali-activated concrete (AAC) has become a hot topic due to the contribution to sustainability in construction industry. AAC has comparable compressive strength compared to the ordinary Portland cement concrete (OPC) and has many advantages, such as excellent durability and corrosion resistance. However, similar to OPC, AACmaterial still has certain shortcomings such as brittleness, low tensile strength, and poor impact resistance, which can be improved by incorporating fibers in the matrix. This paper considers the basalt fiber-reinforced alkali-activated concrete (BFRAAC), and explores the dynamic compressive and tensile strengths through a series of impact tests. The test results show that the dynamic strength of BFRAAC exhibits significant strain rate effect, that is, the material strength increases with the strain rate. Compared to the compressive strength of the material, the strain rate sensitivity of its tensile strength is more marked. Based on the test results, empirical formulas describing the relation between dynamic strength and strain rate of BFRAAC are proposed.

scholarly journals Practical Prediction Models of Tensile Strength and Reinforcement-Concrete Bond Strength of Low-Calcium Fly Ash Geopolymer Concrete

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 875
Author(s):  
Chenchen Luan ◽  
Qingyuan Wang ◽  
Fuhua Yang ◽  
Kuanyu Zhang ◽  
Nodir Utashev ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Bond Strength ◽  
Prediction Models ◽  
Splitting Tensile Strength ◽  
Geopolymer Concrete ◽  
Structural Factors ◽  
Test Results ◽  
Portland Cement Concrete ◽  
Low Calcium

There have been a few attempts to develop prediction models of splitting tensile strength and reinforcement-concrete bond strength of FAGC (low-calcium fly ash geopolymer concrete), however, no model can be used as a design equation. Therefore, this paper aimed to provide practical prediction models. Using 115 test results for splitting tensile strength and 147 test results for bond strength from experiments and previous literature, considering the effect of size and shape on strength and structural factors on bond strength, this paper developed and verified updated prediction models and the 90% prediction intervals by regression analysis. The models can be used as design equations and applied for estimating the cracking behaviors and calculating the design anchorage length of reinforced FAGC beams. The strength models of PCC (Portland cement concrete) overestimate the splitting tensile strength and reinforcement-concrete bond strength of FAGC, so PCC’s models are not recommended as the design equations.

Life cycle assessment and cost analysis of fly ash–rice husk ash blended alkali-activated concrete

2021 ◽  
Vol 295 ◽  
pp. 113140
Author(s):  
Sarah Fernando ◽  
Chamila Gunasekara ◽  
David W. Law ◽  
M.C.M. Nasvi ◽  
Sujeeva Setunge ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Fly Ash ◽  
Cost Analysis ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Alkali Activated Concrete ◽  
Alkali Activated

scholarly journals Alkali-activated concrete with Serbian fly ash and its radiological impact

2017 ◽  
Vol 168 ◽  
pp. 30-37 ◽  
Author(s):  
Cristina Nuccetelli ◽  
Rosabianca Trevisi ◽  
Ivan Ignjatović ◽  
Jelena Dragaš
Keyword(s):  
Fly Ash ◽  
Radiological Impact ◽  
Alkali Activated Concrete ◽  
Alkali Activated

scholarly journals Alkali-Activated Slag/ Fly Ash Concrete: Mechanism, Properties, Hydration Product and Curing Temperature

2020 ◽  
Vol 9 (9) ◽  
pp. 204-215
Keyword(s):  
Fly Ash ◽  
Hydration Product ◽  
Test Methods ◽  
Curing Temperature ◽  
Environmental Friendliness ◽  
Alkali Activated Slag ◽  
Fly Ash Concrete ◽  
Activated Slag ◽  
Alkali Activated Concrete ◽  
Alkali Activated

Alkali-activated concrete (AAC) is mounting as a feasible alternative to OPC assimilated to reduce greenhouse gas emanated during the production of OPC. Use of pozzolana results in gel over-strengthening and fabricate less quantity of Ca(OH)2 which provide confrontation to concrete against hostile environment. (AAC) is potential due to inheriting the property of disbursing CO2 instantly from the composition. Contrastingly an option to ordinary Portland cement (OPC), keeping this fact in mind the goal to evacuate CO2 emits and beneficiate industrial by-products into building material have been taken into consideration. Production of alkali-activated cement emanates CO2 nearly 50-80% less than OPC. This paper is the general assessment of current report on the fresh and hardened properties of alkali-activated fly ash (AAF), alkali-activated slag (AAS), and alkali activated slag and fly ash (AASF) concrete. In the recent epoch, there has been a progression to blend slag with fly ash to fabricate ambient cured alkali-activated concrete. Along with that the factors like environmental friendliness, advanced studies and investigation are also mandatorily required on the alkali activated slag and fly ash concrete. In this way, the slag to fly ash proportion impacts the essential properties and practical design of AAC. This discusses and reports the issue in an intensive manner in the following sections. This will entail providing a good considerate of the following virtues like workability, compressive strength, tensile strength, durability issues, ambient and elevated-temperature curing of AAC which will improve further investigation to elaborate the correct test methods and to commercialize it.

scholarly journals Characterization of lightweight concrete made of palm oil clinker aggregates

2018 ◽  
Vol 250 ◽  
pp. 03002 ◽  
Author(s):  
Muhammad Sazlly Nazreen ◽  
Roslli Noor Mohamed ◽  
Mariyana Aida Ab Kadir ◽  
Nazry Azillah ◽  
Nazirah Ahmad Shukri ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Palm Oil ◽  
Lightweight Concrete ◽  
Flexural Modulus ◽  
Pulse Velocity ◽  
Normal Weight ◽  
Lightweight Aggregate Concrete ◽  
Fine Aggregate ◽  
Test Results ◽  
Aggregate Concrete

Lightweight concrete (LWC) has been identified as an innovative technique for construction purposes. Lightweight concrete can be categorized into three different types which are no-fine aggregate concrete, lightweight aggregate concrete and aerated concrete. This paper studied the characteristic of the lightweight concrete in term of mechanical properties utilizing the palm oil clinker (POC) as lightweight aggregates. Two mixes of lightweight concrete were developed, namely as POCC100 and POCC50 where each mix utilized 100% and 50% of total replacement to fine and coarse aggregates, respectively. The fresh and hardened POC concrete was tested and compared to the normal concrete (NC). The hardened state of the concrete was investigated through density test, ultrasonic pulse velocity, cube compressive, splitting tensile, flexural, modulus of elasticity and Poisson's ratio. From density test results, POC falls into the category of lightweight concrete with a density of 1990.33 kg/m3, which are below than normal weight concrete density. The mechanical properties test results on POCC100 and POCC50 showed that the concrete compressive strength was comparable about 85.70% and 96% compared to NC specimen, respectively. For the flexural strength, POCC50 and POCC100 were comparable about 98% and 97% to NC specimen, respectively. While splitting tensile strength of POCC50 and POCC100 was only 0.6% and 4% lower than NC specimen, respectively. In terms of sustainability of solid waste management, the application of the POC in construction will reduce the redundant of by-products resulted from the palm oil industries. After undergoing various testing of concrete mechanical properties, it can be concluded that POC aggregates was compatible to be used in ligtweight concrete mix proportion.

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