The Mechanical Properties of Lightweight Concrete under Different Factors

2014 ◽  
Vol 665 ◽  
pp. 203-207
Author(s):  
Xi Liu ◽  
Bei Bei Lv ◽  
Tao Wu

By choosing domestic ceramsite as lightweight aggregate, mixing with active mineral admixture (fly ash) and the water reducing agent, and adopting the method of absolute volume to design the three ceramsite concretemixture ratio, 27 groups, 243 lightweight aggregate ceramsite concrete test cubes of 100mm×100mm×100mm are obtained for compressive strength test, and the physical and mechanical properties of the aggregate are studied. At the same time, through the systematic test, the influences of the aggregate strength, water-binder ratio, fly-ash content, etc on ceramsite concrete are studied. Finally the best mixture ratio scheme for ceramsite concrete is gained, providing theoretical basis for the application of lightweight aggregate concrete.

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Songlin Zhang ◽  
Kang Yuan ◽  
Jiaming Zhang ◽  
Junlin Guo

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.


2011 ◽  
Vol 374-377 ◽  
pp. 1477-1480
Author(s):  
Jun Liu ◽  
Chang Wei Xu ◽  
Yun Zhang ◽  
Bing Zhang

This paper introduced a method of saving materials and energy through making small hollow blocks with the slag admixture in the lightweight aggregate concrete. Through orthogonal design, this paper took slag content, water binder ratio and admixture dosage into consideration and focused on influence of slag content on the physical and mechanical properties of lightweight aggregate concrete small hollow blocks. The results show that: when water binder ratio ,admixture dosage and curing system keep a fixed level, during the range of slag content 30%-40%, with the increase in slag content, the compressive and bending strength of small hollow block increased first and then decreased; water content and absorption and relative water moisture content decreased first and then increased; frost resistance increased then decreased; softening coefficient first increased and then decreased. When the slag content is 35%, the physical and mechanical properties of lightweight aggregate concrete small hollow block are the best, and all the indexes of physical and mechanical properties can meet the standard requirements non-bearing lightweight aggregate concrete hollow block. The curing system significantly affected the strength of the lightweight aggregate concrete small hollow block, and the block strength cured under the standard condition was higher than those under natural condition.


2013 ◽  
Vol 857 ◽  
pp. 105-109
Author(s):  
Xiu Hua Zheng ◽  
Shu Jie Song ◽  
Yong Quan Zhang

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.


2018 ◽  
Vol 926 ◽  
pp. 140-145 ◽  
Author(s):  
Małgorzata Mieszczak ◽  
Lucyna Domagała

The paper presents the results of tests conducted on two lightweight aggregate concretes made of new national Certyd artificial aggregate. This research is intended to first application of lightweight concrete to construct large-span post-tensioned slab. In addition to mechanical properties development, shrinkage and creep during 3 months of loading were tested. The obtained results are compared with theoretical results predicted by standard. Conducted tests indicated, that measured values of shrinkage and creep are significantly lower than predicted ones. This is promise for application of tested concrete in construction of post-tensioned slabs.


2020 ◽  
Vol 10 (21) ◽  
pp. 7871
Author(s):  
Jung-Nan Chang ◽  
Tung-Tsan Chen ◽  
Chang-Chi Hung ◽  
Her-Yung Wang

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.


2011 ◽  
Vol 117-119 ◽  
pp. 1302-1305
Author(s):  
Ning Liao ◽  
Hong Zhi Cui

This research is one part of preliminary work for integrated structural-functional energy storage concrete by using porous artificial lightweight aggregate and phase change material. Lightweight aggregate concrete (LWAC) has been applied more and more extensively in recent years, but high water absorption of porous artificial lightweight aggregate (LWA) is inconvenient for LWAC production. In order to improve LWA application, in this paper, two aspects of lightweight aggregate (LWA) study have been carried out, namely, a) LWA surface modification. The effects of different concentration of surface modifier on water absorption of modified LWA were studied. b) Mechanical properties of lightweight aggregate concrete made of the unmodified and modified LWAs Through comparing the water absorption of unmodified and modified LWAs, it can be known that the surface modification for LWA can reduce the water absorption obviously. The three kinds of lightweight concrete possess nearly same strength at 7-day and, at 28-day, the strength of LWAC using 1:20 modified LWA is highest and that of LWAC using 1:5 modified LWA is lowest. 28 days compressive strength of LWAC using 1:20 modified LWA could be up to 46.1MPa.


2014 ◽  
Vol 599 ◽  
pp. 74-77
Author(s):  
Ping Yang ◽  
Wei Xia Zhao ◽  
Jin Chao Yang ◽  
Li Liu ◽  
Mian Li Cao

This paper discusses the reason of segregation of expanded perlite lightweight aggregate concrete. By adding fly ash, high effective admixture, the expanded perlite pre-wetting and so on,the expanded perlite lightweight concrete,CL5-CL10,was confect with good workability, homogeneity, no bleeding and segregation, easy casting and excavation.


2021 ◽  
Vol 25 (02) ◽  
pp. 24-35
Author(s):  
Zahraa A. Mirza ◽  
◽  
Nibras N. Khalid ◽  

Lightweight concrete reduces the total dead load of structural elements and seismic loads significantly. This paper presents the production Attapulgite Lightweight aggregate concrete (ALWAC) and its effect on the flexural behavior of reinforced concrete beams. Attapulgite was treated with sodium hypochlorite of 6% concentration for 24 hours. The variable considered was the aluminum waste (AW), used as a fiber, of fraction (0, 0.5 and 1%) by concrete volume. Behavior was investigated in terms of cracking and ultimate load, load-deflection relationship, failure mode, crack patterns and flexural ductility. The mechanical properties of the ALWAC were studied. It was observed that, Attapulgite improves the mechanical properties of concrete when comparing the experimental value with theoretical ones for the reference mixture. AW has a disparate effect on the mechanical properties of ALWAC. The increase in the proportions of AW showed an increase in the cracking load and decrease in the ultimate load by 37.14% and 22.45 %, respectively, at AW of 1%. Experimental value of ultimate load in all beams was higher than the theoretical value (ACI simplified method). AW increases the deflection at the same magnitude of applied load, and reduces the number and propagation of the flexural cracks in beams. All beams exhibited a typical tension failure mode and failed in ductile manner.


Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5922
Author(s):  
Patrycja Przychodzień ◽  
Jacek Katzer

Despite the undoubted advantages of using lightweight concrete, its actual use for structural elements is still relatively small in comparison to ordinary concrete. One of the reasons is the wide range of densities and properties of lightweight aggregates available on the market. As a part of the research, properties of concrete based on sintered fly ash were determined. The ash, due to its relatively high density is suitable to be used as a filler for structural concretes. Concrete was based on a mixture of sintered fly ash and exfoliated vermiculite aggregate also tested. The purpose of the research was to determine the possibility of using sintered fly ash as alternative aggregate in structural concrete and the impact of sintered fly ash lightweight aggregate on its physical, mechanical and durability properties. Conducted tests were executed according to European and Polish standards. Created concretes were characterized by compressive strength and tensile strength ranging from 20.3 MPa to 54.2 MPa and from 2.4 MPa to 3.8 MPa, respectively. The lightest of created concretes reached the apparent density of 1378 kg/m3.


Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 948
Author(s):  
Mugahed Amran ◽  
Yeong Huei Lee ◽  
Nikolai Vatin ◽  
Roman Fediuk ◽  
Shek Poi-Ngian ◽  
...  

Foam concrete (FC) serves as an efficient construction material that combines well thermal insulation and structural properties. The studies of material characteristics, including the mechanical, physical, rheological, and functional properties of lightweight concrete, have been conducted rigorously. However, a lack of knowledge on the design efficiency of reinforced FC (RFC) was found in current research trends, compared to reinforced lightweight aggregate concrete. Therefore, this paper presents a review of the performance and adaption in structures for RFC. According to the code specifications, the feasibility investigation was preliminarily determined in structural use through the summary for the mechanical properties of FC of FC’s mechanical properties. For reinforced concrete design, a direct method of reduction factors is introduced to design lightweight aggregate concrete, which is also suggested to be adapted into a lightweight FC design. It was found that flexural shear behavior is a more complex theoretical analysis than flexure. However, a reduction factor of 0.75 was recommended for shear, torsion, and compression; meanwhile, 0.6 for flexural members. Serviceability limit states design should be applied, as the crack was found predominant in RFC design. The deflection controls were recommended as 0.7 by previous research. Research on RFC’s compression members, such as a column or load load-bearing wall, were rarely found. Thus, further study for validating a safe design of RFC applications in construction industries today is highly imperative.


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