Influence of Physical Strengthening Technology on the Properties of Recycled Coarse Aggregate

2017 ◽  
Vol 727 ◽  
pp. 1074-1078
Author(s):  
Gong Bing Yue ◽  
Qiu Yi Li ◽  
Gao Song
Keyword(s):  
Water Absorption ◽  
Bulk Density ◽  
Apparent Density ◽  
Void Ratio ◽  
Coarse Aggregate ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates ◽  
Absorption Ratio ◽  
Index Value

This paper studied the properties improvement of recycled coarse aggregate by the physical strengthening technology (particle-shaping method). Through the analysis for obtained properties which consist of density, crush index, bulk density and water absorption. etc of recycled coarse aggregates in different strengthening technologies, the categories of recycled coarse aggregate could be assessed and determined. The results showed that ordinary recycled coarse aggregates that was handled twice by using particle shaping equipment can achieve the standard of class Iaggregates and its water absorption ratio at 24h was 1.2%, the apparent density reached 2575kg/m3, crush index value was 9%, the void ratio was 45%, all property parameters were close to those of natural coarse aggregate.

scholarly journals Quantitative Analysis of Surface Attached Mortar for Recycled Coarse Aggregate

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 257
Author(s):  
Guoying Liu ◽  
Qiuyi Li ◽  
Jialin Song ◽  
Liang Wang ◽  
Haibao Liu ◽  
...  
Keyword(s):  
Water Absorption ◽  
Apparent Density ◽  
Coarse Aggregate ◽  
Mechanical Action ◽  
Hardened Cement ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates ◽  
Before And After ◽  
Strengthening Technique

Due to the large amount of old hardened cement mortar attached to the surface of aggregate and the internal micro-cracks formed by the crushing process, the water absorption, apparent density, and crushing index of recycled coarse aggregate are still far behind those of natural coarse aggregate. Based on the performance requirements of different qualities of recycled coarse aggregate, the performance differences of recycled coarse aggregate before and after physical strengthening were observed. The results showed that the physical strengthening technique can remove old hardened mortar and micro powder attached to the surface of recycled coarse aggregate by mechanical action, which can effectively improve the quality of recycled coarse aggregate. The optimum calcination temperature of the recycled coarse aggregate was 400 °C and the grinding time was 20 min. The contents of the attached mortar in recycled coarse aggregates of Class I, II, and III were 7.9%, 22.8%, and 39.7%, respectively. The quality of recycled coarse aggregate was closely related to the amount of mortar attached to the surface. The higher the mortar content, the higher the water absorption, lower apparent density, and higher crushing index of the recycled coarse aggregate.

Organic Pretreatment of Recycled Aggregates of Rural Construction Waste

2012 ◽  
Vol 161 ◽  
pp. 1-5
Author(s):  
Jun Liu ◽  
Yao Li ◽  
Xu Ming Wang ◽  
Run Qing Liu
Keyword(s):  
Acetic Acid ◽  
Water Absorption ◽  
Absorption Rate ◽  
Coarse Aggregate ◽  
Construction Waste ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates ◽  
Water Absorption Rate ◽  
Pretreatment Technology ◽  
Rural Construction

Through using acetic acid resin, asphalt and urea resin organic pretreatment methods to pretreat the surface of rural construction waste, and testing of crush index and water absorption rate of recycled coarse aggregate after pretreatment, the research for the influence of organic pretreatment technology on physical and mechanical performance of recycled coarse aggregate. The results prove that organic infiltrating pretreatment technology can effectively enhance the density of the coarse aggregate and decrease the crush of recycled coarse aggregate index, in a certain extent. The crush index of recycled coarse aggregates after organic pretreatment decreases at almost 17.63%, what’s more, organic pretreatment technology can decrease the water absorption rate of coarse aggregate by a large margin. The water absorption rate of coarse aggregate can be reduced to a minimum of 2.03% which closes to the level of natural aggregates. Because of urea resin solidified into film at fast speed, high integrity and high wear resistance, and relatively cheap, urea resin’s pretreatment effects on recycled coarse aggregates is better than acetic acid resin and asphalt.

Research on Properties of Recycled Coarse Aggregate

2013 ◽  
Vol 779-780 ◽  
pp. 144-150
Author(s):  
Yong Jun Qin ◽  
Rui Liang ◽  
Aihemaiti Yibulayin ◽  
Jiang Yu ◽  
Lei Li
Keyword(s):  
Water Absorption ◽  
Apparent Density ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Test Results ◽  
Particle Content ◽  
National Regulation ◽  
Recycled Coarse Aggregate ◽  
Powder Content

The performance of recycled coarse aggregate has significant effects on recycled concrete. The performance of recycled coarse aggregate were tested according to Recycled coarse aggregate for concrete (GB/T 25177-2010). The Result showed that the recycled coarse aggregate grading in accordance with regulation requirements, and compared with the natural coarse aggregate: high powder content and water absorption, low needle and plate particle content, low apparent density, compression capability as low as soundness. And the property of recycled coarse aggregate after cleaning has the performance of guaranteeing the quality by using. Through the test results and consult the national regulation, the recycled coarse aggregate in Xinjiang can be preliminary division to the categories of I and II.

Coarse Aggregates Obtained from Red Mud via Pelletizing Process

2014 ◽  
Vol 798-799 ◽  
pp. 492-497
Author(s):  
Luiz Franscisco Isaias ◽  
Luana Spricigo Furlan ◽  
Fernando Pelisser ◽  
Michael Peterson ◽  
Oscar Rubem Klegues Montedo ◽  
...  
Keyword(s):  
Water Absorption ◽  
Clay Mineral ◽  
Apparent Density ◽  
Red Mud ◽  
Mineral Content ◽  
Coarse Aggregate ◽  
Mineral Contents ◽  
Coarse Aggregates ◽  
Test Pieces ◽  
Processing Properties

The aim of this work was the obtaining coarse aggregate from red mud (RM) focused on the processing properties. RM and two clays (A and B) were selected from Pará state (Brazil) and characterized by XRD, XRF and HSM. Six compositions were planned by mixture design. RM amount varied from 80 to 100wt%. Compositions were pelletized in a pelletizer disc, resulting test pieces of 4 to 19 mm (diameter). Firing temperatures ranged from 1150 to 1190 oC and holding time from 15 to 90 min. Pelletizing humidity, dry friability, water absorption, and apparent density were determined. Clays A and B presented clay mineral content about 67 and 12 wt%, quartz 25 and 82wt%, respectively. The higher clay mineral contents the smaller dry friability and water absorption. Appropriated clay mineral contents and firing parameters is needed in order to satisfy processing and final properties requirements, being possible to obtain aggregates from pelletizing process.

scholarly journals Effect of Recycled Coarse Aggregate and Bagasse Ash on Two-Stage Concrete

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 556
Author(s):  
Muhammad Faisal Javed ◽  
Afaq Ahmad Durrani ◽  
Sardar Kashif Ur Rehman ◽  
Fahid Aslam ◽  
Hisham Alabduljabbar ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Construction Material ◽  
Strength Reduction ◽  
Recycled Aggregate ◽  
Two Stage ◽  
Conventional Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Numerous research studies have been conducted to improve the weak properties of recycled aggregate as a construction material over the last few decades. In two-stage concrete (TSC), coarse aggregates are placed in formwork, and then grout is injected with high pressure to fill up the voids between the coarse aggregates. In this experimental research, TSC was made with 100% recycled coarse aggregate (RCA). Ten percent and twenty percent bagasse ash was used as a fractional substitution of cement along with the RCA. Conventional concrete with 100% natural coarse aggregate (NCA) and 100% RCA was made to determine compressive strength only. Compressive strength reduction in the TSC was 14.36% when 100% RCA was used. Tensile strength in the TSC decreased when 100% RCA was used. The increase in compressive strength was 8.47% when 20% bagasse ash was used compared to the TSC mix that had 100% RCA. The compressive strength of the TSC at 250 °C was also determined to find the reduction in strength at high temperature. Moreover, the compressive and tensile strength of the TSC that had RCA was improved by the addition of bagasse ash.

scholarly journals Mechanical Properties of Geopolymer Concrete Made With Partial Replacement of Coarse Aggregate by Recycled Aggregate

2019 ◽  
Vol 9 (1) ◽  
pp. 2301-2304 ◽  
Keyword(s):  
Mechanical Properties ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Construction is the one the fast growing field in the worldwide. There are many environmental issues connected with the manufacture of OPC, at the same time availability of natural coarse aggregate is getting reduced. Geopolymer binder and recycled aggregates are promising alternatives for OPC and natural coarse aggregates. It is produced by the chemical action of inorganic molecules and made up of Fly Ash, GGBS, fine aggregate, coarse aggregate and an alkaline solution of sodium hydroxide and sodium silicate. 10 M sodium hydroxide and sodium silicate alkali activators are used to synthesis the geopolymer in this study. Recycled aggregates are obtained from the construction demolished waste. The main focus of this work is to find out the mechanical properties of geopolymer concrete of grade G40 when natural coarse aggregate(NCA) is replaced by recycled coarse aggregate in various proportions such as 0%, 10%, 20%, 30%,40% and 50% and also to compare the results of geopolymer concrete made with recycled coarse aggregates(RAGPC) with geopolymer concrete of natural coarse aggregate(GPC) and controlled concrete manufactured with recycled aggregates(RAC) and controlled concrete of natural coarse aggregates(CC) of respective grade. It has been observed that the mechanical properties are enhanced in geopolymer concrete, both in natural coarse aggregate and recycled coarse aggregate up to 30% replacement when it is compared with the same grade of controlled concrete.

scholarly journals FORMULATION DEVELOPMENT AND EVALUATION OF FAST DISINTEGRATING TABLETS OF CINITAPRIDE HYDROGEN TARTARATE BY USING DIRECT COMPRESSION TECHNIQUE

2017 ◽  
Vol 9 (6) ◽  
pp. 98 ◽  
Author(s):  
Krishna Mohan Chinnala ◽  
Sirish Vodithala
Keyword(s):  
Drug Release ◽  
Water Absorption ◽  
Bulk Density ◽  
Direct Compression ◽  
Disintegration Time ◽  
Absorption Ratio ◽  
Wetting Time ◽  
Tapped Density ◽  
Fast Disintegrating Tablets

Objective: In the present study, efforts were taken to develop fast disintegrating tablets of Cinitapride hydrogen tartrate, is a gastro-prokinetic agent and antiulcer agent with an objective to achieve rapid disintegration, and further improving the bioavailability of the drug. Also, to resolve the swallowing problems (Dysphasia) in pediatric, geriatric patients by rapid disintegration in saliva and improve the patient compliance.Methods: Fast disintegrating tablets were prepared by direct compression method using superdisintegrants like crospovidone (CP), croscarmellose sodium (CCS), sodium starch glycolate (SSG) and combination of super-disintegrants in different concentrations. The prepared formulations were evaluated for the pre-compression parameters like bulk density, tapped density, Carr’s compressibility, Hausner’s ratio and angle of repose. The prepared batches of fast disintegrating tablets of Cinitapride hydrogen tartarate were evaluated for hardness, weight variation, thickness, friability, drug content, disintegration time, wetting time, water absorption ratio, and in vitro dissolution profile.Results: Bulk density and tapped density were found in the range of 0.412–0.432 g/cc and 0.507–0.528 g/cc respectively. In all formulations, tablet weight and thickness were within mean±9.5% and mean±5% respectively. Wetting time values lie between 19.76 to 39.53 sec. Water absorption ratio ranged from 57.30 to 78.82 %. The in vitro disintegration time for all the 12 formulations varied from 17.43 to 38.61 seconds. Formulation F8 which contained crosspovidone have recorded drug release 96.94±0.47% at the end of 30 min.Conclusion: The formulation containing crospovidone (F8) showed better performance in terms of disintegration time and drug release when compared to other formulations.

scholarly journals Capillary Water Absorption Characteristics of Recycled Concrete in Freeze-Thaw Environment

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Qianhui Xiao ◽  
Xiaolin Liu ◽  
Jisheng Qiu ◽  
Yangyang Li
Keyword(s):  
Prediction Model ◽  
Water Absorption ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Capillary Water ◽  
Replacement Rate ◽  
Capillary Water Absorption ◽  
Freeze Thaw ◽  
Recycled Coarse Aggregate ◽  
Absorption Characteristics

In order to study the capillary water absorption characteristics of recycled concrete (RAC) with different replacement rates of recycled coarse aggregate (0, 20%, 40%, and 60%) in freeze-thaw environment, the standard test method of measuring the water absorption of hydraulic cement concrete (ASTM C1585-13) was adopted, and the influence mechanism of freeze-thaw cycle and replacement rate of recycled coarse aggregate on the capillary water absorption of RAC was analyzed, and a prediction model of initial capillary water absorption of RAC in freeze-thaw environment was established. The results show that when the freeze-thaw environment is the same, the greater the replacement rate of recycled coarse aggregate, the greater the cumulative water absorption of RAC, the faster the initial capillary water absorption, and the stronger the capillary water absorption; when the freeze-thaw environment is different, the more the freeze-thaw cycles, the greater the cumulative water absorption of RAC with the same replacement rate of recycled coarse aggregate, the faster the initial capillary water absorption, and the stronger the capillary water absorption. The prediction model of RAC initial capillary water absorption established by regression analysis has high accuracy, which can be used to predict RAC capillary water absorption performance and provide theoretical basis for the research of RAC frost resistance durability.

Influence of Morphology of Cathode-Ray Tube Glass as Coarse Aggregates on Compressive Strength and Water Absorption of Concrete

2018 ◽  
Vol 280 ◽  
pp. 399-409
Author(s):  
Nurul Noraziemah Mohd Pauzi ◽  
Maslina Jamil ◽  
Roszilah Hamid ◽  
Muhammad Fauzi Mohd Zain
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Coarse Aggregate ◽  
Capillary Water ◽  
Capillary Water Absorption ◽  
Coarse Aggregates ◽  
Concrete Properties ◽  
Concrete Production ◽  
Cathode Ray Tube ◽  
Texture Size

The study on the substitution for natural coarse aggregates using waste CRT funnel glass in spherically shapes is still limited. In this paper, the waste CRT glass has been processed to form a spherical CRT glass (GS) and crushed CRT glass (GC), which were used as a coarse aggregate in concrete production. Results indicated that the inclusion of GS and GC has lower the compressive strength and decreased the rate of capillary water absorption of concrete. It was demonstrated that the morphology properties of GS and GC (shape, surface texture, size, grading) is significantly affected the concrete properties.

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