scholarly journals Evaluation of Heat Insulation and Surface Resistivity of Mineral Lightweight Aggregate Concrete(MLAC)

2020 ◽  
Vol 10 (21) ◽  
pp. 7871
Author(s):  
Jung-Nan Chang ◽  
Tung-Tsan Chen ◽  
Chang-Chi Hung ◽  
Her-Yung Wang
Keyword(s):  
Heat Insulation ◽  
Lightweight Aggregate ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Unit Weight ◽  
Lightweight Aggregate Concrete ◽  
Control Group ◽  
K Value ◽  
Aggregate Concrete ◽  
Binder Ratio

In this study, the fixed water/binder ratio is 0.40, four mineral admixtures: fly ash (FA), blast furnace slag (BFS), desulphurization slag (DLS), and glass LED powder (GLP), were added to lightweight aggregate concrete (LWAC), replacing 10% or 30% of the cement content, to study their heat insulation efficiency and engineering performance and to compare the economic impact of mineral admixtures on LWAC. In terms of heat insulation, the thermal conductivity (K value) of the controlled sample was 0.484 kcal/(m.h. °C) and the addition of mineral admixtures changed the concrete unit weight and water absorption ratio, thus reducing the K value by 0.41% to 25.71% and improving the heat insulation. As the mineral admixture hydration products and chemical contents differed, the heat insulation of the LWAC varied as well. The study indicated that the heat insulation is the greatest in concrete with the addition of 30% FA, followed by concrete with the addition of 10% GLP. The addition of mineral admixtures is 30%, the resistivity is 72–455% of the control group, and the resistivity of FA and GLP is higher than the control group. The study is indicated that the proper addition of mineral powder material has an apparent effect on increasing heat insulation efficiency.

Permeability of Lightweight Aggregate Concrete with Mineral Admixture

2013 ◽  
Vol 857 ◽  
pp. 105-109
Author(s):  
Xiu Hua Zheng ◽  
Shu Jie Song ◽  
Yong Quan Zhang
Keyword(s):  
Pore Structure ◽  
Lightweight Concrete ◽  
Chloride Ion ◽  
Lightweight Aggregate ◽  
Total Porosity ◽  
Normal Weight ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete

This paper presents an experimental study on the permeability and the pore structure of lightweight concrete with fly ash, zeolite powder, or silica fume, in comparison to that of normal weight aggregate concrete. The results showed that the mineral admixtures can improve the anti-permeability performance of lightweight aggregate concrete, and mixed with compound mineral admixtures further more. The resistance to chloride-ion permeability of light weight concrete was higher than that of At the same strength grade, the anti-permeability performance of lightweight aggregate concrete is better than that of normal weight aggregate concrete. The anti-permeability performance of LC40 was similar to that of C60. Mineral admixtures can obviously improve the pore structure of lightweight aggregate concrete, the total porosity reduced while the pore size decreased.

Experiment Study on Mechanical Performance of Shale Lightweight Aggregate Concrete

2012 ◽  
Vol 530 ◽  
pp. 80-84 ◽  
Author(s):  
Lin Li ◽  
Qing Wang ◽  
Yu Wang ◽  
Zhao Yang Ding
Keyword(s):  
High Performance ◽  
Large Scale ◽  
Mechanical Performance ◽  
Lightweight Aggregate ◽  
High Strength ◽  
Mineral Admixtures ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Volume Stability ◽  
Binder Ratio

High performance lightweight aggregate concrete is a kind of lightweight environment-protected building material with high strength, good workability, volume stability and durability, which is widely used in large scale engineering and some important engineering. In this paper water-binder ratio, fly ash content, pre-wetting time, sand ratio were tested to explore the comprehensive strength of lightweight aggregate concrete(LWAC). SEM was used to observe the microstructure characteristics of the specimens. The results showed that LWAC produced in the experiment present good performance, whose apparent density was 1760 Kg/m3～1930Kg/m3, 28d compressive strength was 55MPa～60MPa. Reasonable amounts of sand ratio(38%) and mineral admixtures(10%) were exited and the self-strength of lightweight aggregate played an important role in the preparation of LWAC. In the meanwhile, lightweight aggregates which were pre-wetted effectively increased the later strength.

scholarly journals Effects of Multiple Supplementary Cementitious Materials on Workability and Segregation Resistance of Lightweight Aggregate Concrete

2018 ◽  
Vol 10 (11) ◽  
pp. 4304 ◽  
Author(s):  
Afonso Solak ◽  
Antonio Tenza-Abril ◽  
José Saval ◽  
Victoria García-Vera
Keyword(s):  
Lightweight Aggregate ◽  
Posidonia Oceanica ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Mineral Admixtures ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Beneficial Effects ◽  
Binder Ratio ◽  
Different Grain Size

In view of the global sustainable development, it is imperative that supplementary cementing materials (SCM) be used for replacing cement in the concrete industry and several researchers have shown that mineral admixtures can enhance the workability of lightweight aggregate concrete (LWAC) mixture and its strength. In view of the beneficial effects of using SCM in LWAC, this article aims to verify the possible influence of the use of different types of SCM in the segregation phenomenon of LWAC. Three different SCM were studied: Silica Fume (SF), Fly Ash (FA) and Posidonia oceanica Ash (PA). For each SCM, three mixtures were prepared, considering three different percentage substitutions of cement. An image analysis technique was applied to estimate the segregation in each sample. The results show that a substitution of cement by other materials with different grain size, considering a constant water binder ratio, may also result in a variation of the consistency of concrete and the viscosity of the mortar matrix, which may contribute to increase or reduce segregation.

scholarly journals Experimental Study on Autogenous and Drying Shrinkage of Steel Fiber Reinforced Lightweight-Aggregate Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Shunbo Zhao ◽  
Changyong Li ◽  
Mingshuang Zhao ◽  
Xiaoyan Zhang
Keyword(s):  
Steel Fiber ◽  
Volume Fraction ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Aggregate Concrete ◽  
Binder Ratio ◽  
Water To Binder Ratio

Steel fiber reinforced lightweight-aggregate concrete (SFRLAC) has many advantages applied in structural engineering. In this paper, the autogenous shrinkage and drying shrinkage of SFRLAC for up to 270 days were measured, considering the effects of types of coarse and fine aggregates with the changes of water-to-binder ratio and volume fraction of steel fiber, respectively. The properties of mix workability, apparent density, and compressive strength of SFRLAC were also reported and discussed in relation to above factors. Test results show that the development of autogenous and drying shrinkage of SFRLAC was fast within 28 days and tended to be steady after 90 days. The development of autogenous shrinkage of SFRLAC reduced with the increasing water-to-binder ratio and by using the expanded shale with higher soundness and good water absorption, especially at early age within 28 days; the later drying shrinkage was reduced and the development of drying shrinkage was slowed down with the increasing volume fraction of steel fiber obviously; manufactured sand led to less autogenous shrinkage but greater drying shrinkage than fine lightweight aggregate in SFRLAC. The regularities of autogenous shrinkage and drying shrinkage of SFRLAC expressed as the series of hyperbola are analyzed.

scholarly journals Experimental Study on Performance Influencing Factors and Reasonable Mixture Ratio of Desert Sand Ceramsite Lightweight Aggregate Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Songlin Zhang ◽  
Kang Yuan ◽  
Jiaming Zhang ◽  
Junlin Guo
Keyword(s):  
Substitution Rate ◽  
Physical And Mechanical Properties ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Crushing Strength ◽  
Mixture Ratio ◽  
Aggregate Concrete ◽  
Desert Sand ◽  
Binder Ratio ◽  
Water Binder Ratio

The utilization of desert sand for making ceramsite lightweight aggregate concrete is proposed to make full use of local natural resources in the development of a new type of lightweight and load-bearing wall material with good energy conservation, waste utilization, and thermal insulation performances. An orthogonal test was conducted to analyze the effects of the water-binder ratio, sand ratio, desert sand substitution rate, and fly ash content on the slump, apparent density, and tube crushing strength of desert sand ceramsite lightweight aggregate concrete. Thus, the optimal mixture ratio of the desert sand ceramsite concrete was obtained for the LC20 and LC25 strength grades. Based on two reasonable mixture ratios, the physical and mechanical properties of the desert sand ceramsite concrete were investigated. The results revealed that the water-binder ratio, sand ratio, and desert sand substitution rate were the main influencing factors, and the influence law is essentially consistent with that of ordinary desert sand concrete. Based on the reasonable substitution rate of desert sand, the main physical and mechanical properties of the desert sand ceramsite lightweight aggregate concrete, such as the tube crushing strength, tensile strength, and thermal conductivity, satisfied the requirements of the Chinese code’s specifications. In summary, desert sand can replace ordinary sand in ceramsite lightweight aggregate concrete for the production of new lightweight and load-bearing wall materials.

Research on Influences of Activity Mineral Admixture on Workability and Mechanical Properties of High Strength Lightweight Aggregate Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 861-865
Author(s):  
Xiang Dong ◽  
Jian Ming Gao ◽  
Ai Yu Hu
Keyword(s):  
Mechanical Properties ◽  
Low Cost ◽  
Lightweight Aggregate ◽  
High Strength ◽  
Industrial Wastes ◽  
Mineral Admixture ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Granulated Blast Furnace Slag ◽  
Better Than

Aiming at the high expense of high strength lightweight aggregate concrete (HSLWAC), low-cost HSLWAC was produced making use of the industrial wastes including fly-ash (FA) and ground granulated blast furnace slag (GGBS) as admixture, and the influences of these admixtures on the workability and mechanical properties of HSLWAC were studies. Result shows that HSLWAC whose cubic compressive strength is high to 70MPa at the age of 28d can be produced with mixing admixtures; the effect of mixing GGBS to the strength of HSLWAC is better than that of mixing FA; and mixing admixtures is useful for the improvement of the workability of HSLWAC; However, the brittleness of HSLWAC rises with the increase of its strength.

A Review on Frost Resistance of Steel Fiber Reinforced Lightweight Aggregate Concrete

2013 ◽  
Vol 438-439 ◽  
pp. 295-299 ◽  
Author(s):  
Xiao Ke Li ◽  
Wen Hui Song ◽  
Chang Yong Li
Keyword(s):  
Frost Resistance ◽  
Steel Fiber ◽  
Resistance Mechanism ◽  
Lightweight Aggregate ◽  
Steel Fibers ◽  
Mineral Admixture ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Aggregate Concrete ◽  
Cold Area

Compared with ordinay concrete, weight of lightweight aggregate concrete could be lower 20%-40% under same bearing capacity. Mixed with some given steel fibers in it, crack resistance and flexural strength will be improved. Once lightweight aggregate concrete mixed with steel fibers meets the requirements of frost resistance, it could be applied to most civil engineerings in a cold area. In this paper, the frost resistance mechanism of steel fiber reinforced lightweight aggregate concrete is introduced. The research status of frost resistance of steel fiber reinforced lightweight aggregate concrete is reviewed including the effects of water cement ratio, aggregate, mineral admixture and amount of fiber, frost resistance experimatal methods and engineering applications etc. Some further researches are prospected.

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