Performance Studies of Lightweight Concrete Mixtures Made with Rigid Polyurethane Foam Wastes

2012 ◽  
Vol 204-208 ◽  
pp. 4007-4010 ◽  
Author(s):  
Ge Wang ◽  
Ye Qiu Liu ◽  
Ying Cui
Keyword(s):  
Polyurethane Foam ◽  
Packing Density ◽  
Lightweight Concrete ◽  
Drying Shrinkage ◽  
State Standards ◽  
Rigid Polyurethane Foam ◽  
Concrete Shrinkage ◽  
Concrete Mixtures ◽  
Absolute Density ◽  
The Relationship

This paper describes the results of some studies on the properties of lightweight expanded concrete mixtures made with rigid polyurethane foam waste. Experimental study on the mechanical properties of polyurethane foam waste mixed with concrete shrinkage performance and the relationship between packing density and absolute density. The results showed that: Polyurethane foam plastic waste can be used in the preparation of lightweight concrete, the strength with the state standards, and packing density and concrete absolute density with reference line between sex. Drying shrinkage comply with Selih and Bremner lightweight concrete water content to evolution.

scholarly journals A New Approach for Designing Fluid Concrete with Low Cement Content: Optimization of Packing Density of Aggregates

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4082
Author(s):  
Ning Zhang ◽  
Wenqiang Zuo ◽  
Wen Xu ◽  
Shenyou Song
Keyword(s):  
Compression Strength ◽  
Packing Density ◽  
Cement Content ◽  
Drying Shrinkage ◽  
Simple Method ◽  
New Approach ◽  
Concrete Mixtures ◽  
Slump Flow ◽  
Cementitious Binder ◽  
Hardened Properties

The current study aims at proposing a novel and simple method for designing fluid concrete such as self-compacting concrete (SCC) with a low cementitious binder content to reduce the carbon footprint. Different testing methods regarding the packing density of aggregate mixtures are performed and compared. The W/C was determined according to the target compression strength. Slump flow spread is carried out to determine the most appropriate superplasticizer (SP) dosage and aggregate volume fractions and proportions in concrete mixtures. Furthermore, hardened performance, including compression strength and drying shrinkage of the fluid concrete, are characterized. Finally, a mix design process of fluid concrete with low cement content was proposed based on the preferred fresh and hardened properties of the concrete mixtures.

scholarly journals Shrinkage Effects of Using Fly Ash instead of Fine Aggregate in Concrete Mixtures

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Dongsheng Zhang ◽  
Pengfei Han ◽  
Qiuning Yang ◽  
Mingjie Mao
Keyword(s):  
Fly Ash ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Experimental Results ◽  
Fine Aggregate ◽  
Ordinary Concrete ◽  
Concrete Shrinkage ◽  
Substitution Level ◽  
Concrete Mixtures ◽  
Binder Ratio

China is the world’s largest emitter of fly ash, an industrial by-product of coal combustion. Motivated towards greener development, China’s engineering industries must determine how to effectively utilize this by-product, while ensuring environmental and public safety protections. This study investigated the use of fly ash instead of fine aggregate in concrete mixtures with a focus on concrete shrinkage. A series of experiments were performed in which fly ash substitution levels, water-binder ratios, and ambient humidities were each respectively and exclusively varied to determine changes in the concrete’s drying and autogenous shrinkages. Experimental results indicated that the substitution of fly ash consistently decreased the drying shrinkage relative to ordinary concrete; a substitution level of 25% optimally reduced the drying shrinkage by 20.81%. A substitution level of 15% decreased the autogenous shrinkage relative to ordinary concrete, whereas higher levels (25, 35, and 45%) increased it. Ambient humidities also affected the concrete shrinkage, but the water-to-binder ratio effects were negligible. Drying shrinkage largely occurred before 28 d, whereas autogenous shrinkage continued after 28 d. Based on these experimental results, we evaluated common theoretical shrinkage models and subsequently developed a modified shrinkage model for application to concrete containing fly ash as fine aggregate.

Desorption Experimental Analysis and Modeling of Drying Shrinkage and Relative Humidity in Non-Saturated Concrete

2011 ◽  
Vol 368-373 ◽  
pp. 725-731 ◽  
Author(s):  
Ling Yun Meng
Keyword(s):  
Relative Humidity ◽  
Surface Energy ◽  
Capillary Pressure ◽  
Experimental Analysis ◽  
Drying Shrinkage ◽  
Concrete Shrinkage ◽  
Saturated Concrete ◽  
The Relationship ◽  
Over Time

Abstract. The paper investigates the gradient of relative humidity over time at different depth from dried surface and the relationship between relative humidity and concrete shrinkage. It shows that a drop in relative humidity over time is remarkable, and that drying shrinkage is linearly related to humidity. By measuring the weight of the sample and calculation of the capillary pressure, the relationship between the saturation and the capillary pressure is presented. Based on the experiment and Kelvin’s law, a model of shrinkage for non-saturated concrete taking the surface energy into account is presented. A comparison of computed and observed drying shrinkage is made, finding that the two values are in agreement very well.

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