Orthogonal Design Choices Recycled Concrete Load-Bearing Hollow Block

2013 ◽  
Vol 368-370 ◽  
pp. 1090-1094
Author(s):  
Yuan Xu ◽  
Xiao Ping Wang ◽  
Juan Cheng ◽  
Dong Wang

Study four factors - water consumption , water-cement ratio , recycled fine aggregate replacement ratio of recycled coarse aggregate replacement rate - affect the regularity of the load-bearing hollow block compressive strength of recycled concrete by orthogonal test method , the test showed that , water consumption factors affect the compressive strength of recycled concrete block design with than the emphasis on the control of water consumption . Under the test conditions , the optimum mixture ratio of recycled concrete load-bearing block : water consumption of 160 kg / m 3 , the water cement ratio 0.45 , recycled fine aggregate replacement ratio of 30% recycled coarse aggregate replacement ratio of 30% .

2015 ◽  
Vol 744-746 ◽  
pp. 1412-1415 ◽  
Author(s):  
Zong Ming Jia ◽  
Qing Han ◽  
Ming Hao Liu

Designing recycled concrete mixture proportion of different recycled coarse and fine aggregate replacement content by pulp content ,then testing compressive strength and splitting tensile strength. The text results show that: With the increasing of recycled aggregate content , the compressive strength and splitting tensile strength of recycled aggregate concrete trended to decrease. Compared to recycled coarse aggregate, recycled fine aggregate impact on the properties of recycled concrete is greater. Establishing the compressive strength and splitting tensile strength formula of recycled concrete based on a lot of experimental results.


2018 ◽  
Vol 203 ◽  
pp. 06001
Author(s):  
Muhammad Bilal Waris ◽  
Hussain Najwani ◽  
Khalifa Al-Jabri ◽  
Abdullah Al-Saidy

To manage tyre waste and conserve natural aggregate resource, this research investigates the use of waste tyre rubber as partial replacement of fine aggregates in non-structural concrete. The research used Taguchi method to study the influence of mix proportion, water-to-cement ratio and tyre rubber replacement percentage on concrete. Nine mixes were prepared with mix proportion of 1:2:4, 1:5:4 and 1:2.5:3; water-to-cement ratio of 0.25, 0.35 and 0.40 and rubber to fine aggregate replacement of 20%, 30% and 40%. Compressive strength and water absorption tests were carried out on 100 mm cubes. Compressive strength was directly proportional to the amount of coarse aggregate in the mix. Water-to-cement ratio increased the strength within the range used in the study. Strength was found to be more sensitive to the overall rubber content than the replacement ratio. Seven out of the nine mixes satisfied the minimum strength requirement for concrete blocks set by ASTM. Water absorption and density for all mixes satisfied the limits applicable for concrete blocks. The study indicates that mix proportions with fine to coarse aggregate ratio of less than 1.0 and w/c ratio around 0.40 can be used with tyre rubber replacements of up to 30 % to satisfy requirements for non-structural concrete.


2011 ◽  
Vol 368-373 ◽  
pp. 2185-2188
Author(s):  
Ping Hua Zhu ◽  
Xin Jie Wang ◽  
Jin Cai Feng

The properties of recycled coarsee aggregates from repeatedly recycling waste concrete were determined. In this study, five series of concrete mixtures using coarse and fine natural aggregates were prepared, which have the same objective slump value from 35mm to 50mm and different compressive strengths ranging from 25MPa to 60 MPa. These five concretes were crushed, sieved, washed with water, hot treatmented at 300°C before they were used as recycled aggregates. After that, recycled aggregate concrete (RAC) was produced with an objectively compressive strength of 30MPa, in which the recycled coarse aggregate was used as 30%, 70% and 90% replacements of natural coarse aggregate and recycled fine aggregate as 10%, 20%, and 30% replacements of natural fine aggregate. After that, these recycled concretes were used as second recycled aggregates to produce RAC with the same objectively compressive strength of 30MPa. The physical properties of coarse aggregates including apparent density, water absorption, attached mortar content and crushing value were tested and their mineral characteristics were analyzed. The results showed that the quality of recycled coarse aggregates from twicely recycling waste concrete reached the requirements from structural concrete.


2014 ◽  
Vol 665 ◽  
pp. 147-150 ◽  
Author(s):  
Ping Hua Zhu ◽  
Yi Lei

The strength properties of recycled aggregate concrete (RAC) using aggregates from repeatedly recycling concrete waste were studied. The relationships between cube compressive strength and splitting tensile strength and between each strength and replacement ratio of recycled aggregate to natural aggregate were established. The results showed that the strength properties of RAC with the design strength of 30MPa can be satisfied when the quality of recycled coarse and fine aggregates met respectively the needs of Grade II in GB/T25177-2010 and Grade III in GB/T25176-2010, with the replacement ratio to natural coarse aggregate and natural fine aggregate no more than 70% and 50%. Both strengths decreased and then increased for a while before descending again with increasing replacement ratio of recycled coarse aggregate, and decreased continuously with the increase of replacement ratio of recycled fine aggregate. The relationship between cube compressive strength and splitting tensile strength of RAC was found to be exponential function.


This paper explains the combined effect of granite cutting waste and recycled concrete on the workability and mechanical properties of self compacting concrete. Experimental plan is divided in such a way that granite cutting waste is replaced with fine aggregate at 0, 20,40,60,80 and 100% proportions. Recycled concrete is replaced with the coarse aggregate starting from 20 to 100%. Total 36 mixes were designed to check the fresh and hardened properties. Slump flow and T500, v-funnel and L-box test are conducted to know the flow ability and passing ability of concrete. To study the hardened properties compressive strength, flexural strength test values are to be collected.


2012 ◽  
Vol 598 ◽  
pp. 635-639
Author(s):  
Zhao Hua Du ◽  
Jie Wang

In this paper, the mixture ratio of recycled concrete and its fundamental mechanics properties have been researched by experiments, which include the mechanical properties of recycled aggregate, the optimum mix design of the recycled concrete, compressive strength tests on concrete specimens using the broken abandoned concrete rubbles as recycled coarse aggregate, the replacement ratios of recycled coarse aggregate by mass to the natural coarse aggregate are 0, 0.3, 0.5, 0.70 and 1.0 respectively. The influences of the replacement ratio of recycled coarse aggregate by mass to the fundamental properties of the recycled concrete such as the compressive strength,and the elastic modulus are discussed and analyzed.and the optimum replacement ratio of recycled coarse aggregate by mass is suggested. These may be references to the applications of recycled concrete in engineering.


2013 ◽  
Vol 357-360 ◽  
pp. 1282-1285
Author(s):  
Hai Yong Cai ◽  
Li Bin Fu ◽  
Ling Bo Dang

Influence of replacement ratio and water-cement ratio on the recycled concrete mechanical properties were analyzed by testing the compressive strength and tensile strength of the recycled concrete. Results show that the mechanical properties of recycled concrete, compared with common concrete, can meet the requirements of the project. Water-cement ratio has great influence on compressive strength and tensile strength, replacement ratio has obvious influence on compressive strength but little on tensile.


2012 ◽  
Vol 174-177 ◽  
pp. 275-279
Author(s):  
Da Xing Qian ◽  
Ying Wei Yun ◽  
Il Young Jang ◽  
Woo Young Park

In this paper shucking technique is developed to improve the performance of recycled coarse aggregate concrete. Comparison test has been done to demonstrate the good performance of shucking recycled coarse aggregate concrete than that of common recycled concrete. Simultaneously recycled fine aggregate concrete and recycled finely grinded admixture are extracted and studied too. Results show that this new technique can not only improve the performance of recycled material and enlarge recycled material type, but also make waste concrete to be reused completely.


2011 ◽  
Vol 261-263 ◽  
pp. 75-78 ◽  
Author(s):  
Yi Li ◽  
Jun Lin Tao ◽  
Ting Lei ◽  
Jian Jun Xie

Recycled concrete which are made by waste concrete has significance of environmental protection and saving natural resources. But there are different study results of recycled concrete of domestic and foreign scholars, so it is necessary to do the further study of recycled concrete. Compressive strength test of 225 concrete standard cube specimens have been done by Hydraulic Type Universal Testing Machine, and the relationships among recycled concrete compressive strength, age and recycled coarse aggregate replacement ratio have been studied. The results show: the growth rate of early strength of recycled concrete is smaller than natural concrete of the same gradation and the growth rate of later strength of recycled concrete is faster than natural concrete; when the recycled coarse aggregate replacement ratio increases the compressive strength of concrete decreases, and when the recycled coarse aggregate replacement ratio is over 70%, the decrease ranges more apparent.


2020 ◽  
Vol 12 (24) ◽  
pp. 10544
Author(s):  
Chunhong Chen ◽  
Ronggui Liu ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang

Carbonation durability is an important subject for recycled coarse aggregate concrete (RAC) applied to structural concrete. Extensive studies were carried out on the carbonation resistance of RAC under general environmental conditions, but limited researches investigated carbonation resistance when exposed to chloride ion corrosion, which is an essential aspect for reinforced concrete materials to be adopted in real-world applications. This paper presents a study on the carbonation durability of two generations of 100% RAC with the effect of chloride ion corrosion. The quality evolution of recycled concrete coarse aggregate (RCA) with the increasing recycling cycles was analyzed, and carbonation depth, compressive strength and the porosity of RAC were measured before and after chloride ion corrosion. The results show that the effect of chloride ion corrosion negatively affected the carbonation resistance of RAC, and the negative effect was more severe with the increasing recycling cycles of RCA. Chloride ion corrosion led to a decrease in compressive strength, while an increase in carbonation depth and the porosity of RAC. The equation of concrete total porosity and carbonation depth was established, which could effectively judge the deterioration of carbonation resistance of RAC.


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