An Experimental Study on the Self-Consolidating Concrete (SCC) under Hot Weather and Hauling Time

2016 ◽  
Vol 677 ◽  
pp. 3-7 ◽  
Author(s):  
Samer Al Martini ◽  
Mohamed Al Khatib
Keyword(s):  
Fly Ash ◽  
United Arab Emirates ◽  
Construction Material ◽  
Mixing Time ◽  
Weather Conditions ◽  
Construction Sites ◽  
Self Consolidating Concrete ◽  
Durability Properties ◽  
Hot Weather ◽  
Concrete Placement

Self-consolidating-concrete (SCC) has gained wide acceptance in the construction industry given its ability to reduce construction duration and cost. All ready-mix concrete commonly used in hot weather countries, such as United Arab Emirates (UAE), is subjected to continuous agitation during hauling to construction sites. Prolonged mixing, especially at high temperatures can lead to loss of workability and increased difficulties for concrete placement and consolidation. This may result in lower mechanical and durability properties. In this paper, the mechanical and durability properties of self-consolidating concrete (SCC) under hot weather conditions were investigated. Mixing and testing were conducted outdoor at the construction material lab of Abu Dhabi University during last summer of 2014. The test results showed that the mixing time and hot weather adversely affected the fresh properties. The SCC mixtures were continuously mixed for 2 hours under a temperature ranged from 25 to 40 °C, to simulate concrete in a transit truck during transportation to a construction site under hot weather. Polycarboxylate-based high-range water-reducing admixture (PC) and fly ash were incorporated in the investigated SCC mixtures. The results showed that both the compressive strength and durability of SCC were highly affected by fly ash dosage and temperature.Keywords: Hot weather; hauling time, self-consolidating concrete.

Fresh, Durability and Mechanical Behavior of Self Consolidating Concrete Incorporating Fly Ash and Admixture under Hot Weather

2021 ◽  
Vol 904 ◽  
pp. 453-457
Author(s):  
Samer Al Martini ◽  
Reem Sabouni ◽  
Abdel Rahman Magdy El-Sheikh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Weather Conditions ◽  
Chloride Penetration ◽  
The Self ◽  
Fresh Properties ◽  
Self Consolidating Concrete ◽  
Slump Flow ◽  
Hot Weather

The self-consolidating concrete (SCC) become the material of choice by concrete industry due to its superior properties. However, these properties need to be verified under hot weather conditions. The paper investigates the behavior of SCC under hot weather. Six SCC mixtures were prepared under high temperatures. The SCC mixtures incorporated polycarboxylate admixture at different dosages and prolonged mixed for up to 2 hours at 30 °C and 40 °C. The cement paste was replaced with 20% of fly ash (FA). The fresh properties were investigated using slump flow, T50, and VSI tests. The compressive strength was measured at 3, 7, and 28 days. The durability of SCC mixtures was evaluated by conducting rapid chloride penetration and water absorption tests.

A Study on the Application of Artificial Neural Networks on Green Self Consolidating Concrete (SCC) under Hot Weather

2016 ◽  
Vol 677 ◽  
pp. 254-259 ◽  
Author(s):  
Mohamed Al Khatib ◽  
Samer Al Martini
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Fly Ash ◽  
Ambient Temperature ◽  
Back Propagation ◽  
Self Consolidating Concrete ◽  
Feed Forward Back Propagation ◽  
Slump Flow ◽  
Ann Models ◽  
Hot Weather

Self-consolidating concrete (SCC) has recently drawn attention to the construction industry in hot weather countries, due to its high fresh and mechanical properties. The slump flow is routinely used for quality control of SCC. Experiments were conducted by the current authors to investigate the effects of hot weather conditions on the slump flow of SCC. Self-consolidating concrete mixtures were prepared with different dosages of fly ash and superplasticizer and under different ambient temperatures. The results showed that the slump flow of SCC is sensitive to changes in ambient temperature, fly ash dosage, and superplasticizer dosage. In this paper, several artificial neural networks (ANNs) were employed to predict the slump flow of self-consolidating concrete under hot weather. Some of the data used to construct the ANNs models in this paper were collected from the experimental study conducted by the current authors, and other data were gathered from literature. Various parameters including ambient temperature and mixing time were used as inputs during the construction of ANN models. The developed ANN models employed two neural networks: the Feed-Forward Back Propagation (FFBP) and the Cascade Forward Back Propagation (CFBP). Both FFBP and CFBP showed good predictability to the slump flow of SCC mixtures. However, the FFBP network showed a slight better performance than CFBP, where it better predicted the slump flow of SCC than the CFBP network under hot weather. The results in this paper indicate that the ANNs can be employed to help the concrete industry in hot weather to predict the quality of fresh self-consolidating concrete mixes without the need to go through long trial and error testing program.Keywords: Self-consolidating concrete; Neural networks; Hot weather, Feed-forward back-propagation, Cascade-forward back propagation.

Influence of Metakaolin, Fly Ash and Nano Silica on Mechanical and Durability Properties of Concrete

2017 ◽  
Vol 744 ◽  
pp. 8-14 ◽  
Author(s):  
Rabinder Kumar ◽  
Airil Yasreen B. Mohd Yaseen ◽  
Nasir Shafiq ◽  
Asif Jalal
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Construction Material ◽  
Research Work ◽  
Nano Silica ◽  
Durability Properties ◽  
Pozzolanic Material ◽  
Steel Bar ◽  
Extended Approach ◽  
Mechanical Durability

Concrete is widely used construction material for the development of built environment which consumes huge amount of cement, around 4.3 billion metric ton all over the world. Reinforced concrete construction exposed to harsh environment such as chloride bound air causes deterioration in concrete through its pore structure by corroding the steel bar. The use of pozzolanic material i.e. metakaolin (MK), fly ash (FA), silica fume (SF), nano silica (NS) can be used as partially cement replacing material which not only reduces the pores in concrete but improves the mechanical, durability properties and microstructure of concrete. This paper reviews various transport mechanisms involved in ingress of deleterious material and incorporation of MK, FA and NS in concrete and their effects on concrete mechanical and durability properties. However, the research work provides an extended approach to evaluate combine effect using MK, FA, and NS and to produce a concrete with more refined pore structure for aggressive environment.

scholarly journals Assessing the influence of fly ash and polypropylene fiber on fresh, mechanical and durability properties of concrete

2021 ◽  
Author(s):  
Abu Sayed Mohammad Akid ◽  
Saif Hossain ◽  
Md. Imtiaz Uddin Munshi ◽  
Md Manjur A Elahi ◽  
Md. Habibur Rahman Sobuz ◽  
...  
Keyword(s):  
Fly Ash ◽  
Polypropylene Fiber ◽  
Durability Properties

Durability properties of micro-cracked ECC containing high volumes fly ash

2009 ◽  
Vol 39 (11) ◽  
pp. 1033-1043 ◽  
Author(s):  
Mustafa Şahmaran ◽  
Victor C. Li
Keyword(s):  
Fly Ash ◽  
Durability Properties

scholarly journals Indoor Air Quality (IAQ): Accuracy of Natural Ventilation for Temperature, Air Flow Rate and Relative Humidity (RH) in School Building Classrooms

2018 ◽  
Vol 7 (3.9) ◽  
pp. 42
Author(s):  
Norsafiah Norazman ◽  
Adi Irfan Che Ani ◽  
Nor Haslina Ja’afar ◽  
Muhamad Azry Khoiry
Keyword(s):  
Air Quality ◽  
Relative Humidity ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Air Flow ◽  
Weather Conditions ◽  
Potential Health ◽  
The Hours ◽  
Hot Weather

Indoor Air Quality (IAQ) is an essential matter in achieving students’ satisfaction for the learning process. Building’s orientation is a factor that may encourage sufficient natural ventilation for the classroom occupants. Inadequate ventilation is an issue for most existing classrooms. The purpose of this paper is to analyze the accuracy of natural ventilation in classrooms. Therefore, experimental on 20 classrooms has been conducted by using Multipurpose Meter at secondary school buildings in Malaysia. The findings indicated that the accuracy of natural ventilation testing was below the permissible limits throughout the hours monitored, thus this may cause potential health hazards to the students. Temperature and air flow rates were lower than 23 °C and 0.15 m/s respectively, it fulfilled the basic requirements as a standard learning environment. However, measurements taken showed the overall relative humidity (RH) in the classrooms can be categorized as acceptable with 40% to 70% range. On the basis of these findings, it is evident that naturally ventilated classrooms are important especially due to energy efficiency, whereas mechanical ventilation should only be installed as an alternative under extremely hot weather conditions.   

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