scholarly journals Effect of Ground Waste Concrete Powder on Cement Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Xianwei Ma ◽  
Zhenyu Wang

The paste/mortar attached to the recycled aggregate decreases the quality of the aggregate and needs to be stripped. The stripped paste/mortar is roughly 20% to 50% in waste concrete, but relevant research is very limited. In this paper, the effects of ground waste concrete (GWC) powder, coming from the attached paste/mortar, on water demand for normal consistency, setting time, fluidity, and compressive strength of cement were analyzed. The results show that the 20% of GWC powder (by the mass of binder) has little effect on the above properties and can prepare C20 concrete; when the sand made by waste red clay brick (WRB) replaces 20% of river sand, the strength of the concrete is increased by 17% compared with that without WRB sand.

2020 ◽  
Vol 35 (4) ◽  
pp. 347-353
Author(s):  
Sukai Zhuang ◽  
Xinwei Lu

The radiological hazard of building materials originating from clay, rock and other mineral wastes has attracted more attention because they contain natural radionuclides (226Ra, 232Th, and 40K). The activity concentration of radionuclides in red-clay brick samples obtained from three different brickyards in Shangluo, China waHs measured. Various indexes, including radium equivalent activities, Raeq, external hazard index, Hex, internal hazard index, Hin, indoor air absorbed dose rate, D, and annual effective dose, AED, of the aforementioned radionuclides in the bricks were used to assess the radiation hazard for people. The average activity concentrations of 226Ra, 232Th, and 40K were respectively 34.5 ? 1.9, 62.5 ? 2.1, and 713.7 ? 19.8 Bqkg?1 for the studied red-clay bricks. The Raeq values of the red-clay brick samples varied from 167.0 to 184.7 Bqkg?1, which are lower than the limit of 370 Bqkg?1. Moreover, the activity concentrations of natural radionuclides in unfired brick, clay and coal were also determined and the results were compared with that in the red-clay brick samples. This study shows that the red-clay bricks produced in Shangluo, China can be used safely in construction industries.


2013 ◽  
Vol 43 ◽  
pp. 98-106 ◽  
Author(s):  
L. Reig ◽  
M.M. Tashima ◽  
M.V. Borrachero ◽  
J. Monzó ◽  
C.R. Cheeseman ◽  
...  

2014 ◽  
Vol 584-586 ◽  
pp. 1750-1755
Author(s):  
Xiao Lei Chang ◽  
Song Gu ◽  
Zhi Zheng

Compared with natural aggregate, recycled aggregate apparent density, bulk density, porosity, water absorption, large crushing index value, which corresponds to aggregate different sources have different indicators, which largely of recycled concrete limits on the application.. In order to more efficiently improve the utilization of recycled aggregate, ensure the stability production quality of recycled concrete, source unknown and difficult to directly measure its intensity of waste concrete materials, at the time of the preparation of recycled aggregate, it is recommended to repeat loading, using different pressures from different standard strength of recycled concrete coarse aggregate crushed curve to use as a criterion to determine the source of their overall strength. Different in different sources of strength recycled aggregate crushing value mainly reflected on the bond strength.


2014 ◽  
Vol 665 ◽  
pp. 163-166
Author(s):  
Ping Hua Zhu ◽  
Fei Fei Xie ◽  
Qun Xia

In order to explore the possibility of using repeatedly recycling waste concrete as aggregate to produce structural concrete, experimental research was carried out on the structural properties of three kinds of recycled fine aggregate (RFA) with two-regeneration cycles, two single and one mixed. The results showed that the quality of all RFAs meet the needs of Grade Ⅲ in GB/T25177-2010 and Level L in JISA 5023-2000. The degree of performance degradation is observed to enhance with increasing recycling cycle when taking the same preparation process of recycled aggregate.


2021 ◽  
Author(s):  
Obaid Ur Rahman Mahmoodi

This research focuses on the complete recycling of construction and demolition wastes (CDWs) to develop new green geopolymeric binders. An innovative mix design method based on (SiO2/Al2O3) and (Na2O/SiO2) chemical factors and liquids/solids (L/S) ratio was developed. The main focus was to optimize the compressive strengths of mixes incorporating mono, binary and ternary geopolymer systems of concrete waste (CW), red clay brick waste (RCBW) and ceramic tile waste (CTW). The effects of high temperature curing and the addition of supplementary cementitious materials (SCMs) were also investigated. Fresh properties comprising slump flow and setting time and mechanical characteristics including compressive strengths were investigated. Microstructural study was performed utilizing scanning electron microscopy (SEM), energy-dispersive X-Ray spectroscopy (EDS) and X-Ray Diffraction (XRD). This research proved the efficiency of the new mix design method in reaching high compressive strengths of mono-system of RCBW and CTW and all binary and ternary systems of geopolymer binders.


2021 ◽  
Vol 34 ◽  
pp. 102066
Author(s):  
Mostafa Vafaei ◽  
Ali Allahverdi ◽  
Peng Dong ◽  
Nabil Bassim ◽  
Mostafa Mahinroosta

2021 ◽  
Author(s):  
Obaid Ur Rahman Mahmoodi

This research focuses on the complete recycling of construction and demolition wastes (CDWs) to develop new green geopolymeric binders. An innovative mix design method based on (SiO2/Al2O3) and (Na2O/SiO2) chemical factors and liquids/solids (L/S) ratio was developed. The main focus was to optimize the compressive strengths of mixes incorporating mono, binary and ternary geopolymer systems of concrete waste (CW), red clay brick waste (RCBW) and ceramic tile waste (CTW). The effects of high temperature curing and the addition of supplementary cementitious materials (SCMs) were also investigated. Fresh properties comprising slump flow and setting time and mechanical characteristics including compressive strengths were investigated. Microstructural study was performed utilizing scanning electron microscopy (SEM), energy-dispersive X-Ray spectroscopy (EDS) and X-Ray Diffraction (XRD). This research proved the efficiency of the new mix design method in reaching high compressive strengths of mono-system of RCBW and CTW and all binary and ternary systems of geopolymer binders.


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