Owing to the high absorption capacity of recycled aggregate (RA), it is crucial to accurately measure its saturated-surface-dried water absorption (WSSD), which largely affects an …
Download scientific diagram | Water absorption of recycled concrete aggregate (RCA). from publication: The Effect of Curing Conditions on Selected Properties of Recycled Aggregate Concrete | The ...
The high water absorption of RA with a higher water absorption rate causes a decrease in the workability of recycled concrete, which limits the use of RA in concrete (Kumar and Minocha . In addition, the water absorption rate of RA is also closely related to the particle size.
However, because of the higher water absorption of recycled aggregates, drying shrinkage increases with recycled aggregate replacement ratio [32, [60], [61], [62]]. This effect is due to the higher deformability of recycled aggregate concretes, caused mainly by the adhered mortar on the recycled aggregate surface, which also generates …
Published literature indicates that RCA has higher water absorption rates than aggregates due to the high volume fraction of cement mortar adhering to the aggregate particles (Hansen, 1986; Kasami et al, 1998; Shayan and Xu, 2003). The presence of the adherent mortar and brick content in the RCA usually results in a lower relative ...
The high absorption of fine recycled aggregates is indicated as the main difference with respect to fine natural aggregates. This property determines the extra amount of water to be added...
94 study a wide range of recycled aggregates in terms of absorption and with different 95 microstructures, we prepared c ement pastes at different water-to-cement ratios (W/C): …
In this paper, we show that the drying of recycled aggregates for temperatures above the ambient temperature (>30 °C) and at low relative humidity …
This is also reported in literature [61, 69], which noted a higher absorption rate of recycled fine aggregates than that of natural aggregate. In addition, the water absorption of mixes with ...
The high absorption of fine recycled aggregates is indicated as the main difference with respect to fine natural aggregates. This property determines the extra amount of water to be added during ...
CW is generated worldwide and can be safely reused as a recycled aggregate by simply adapting particle size distribution. Several studies have used crushed CW particles like that presented in Fig. 2 as recycled aggregates in concrete. These CW particles are irregular, have sharp edges and may present a smooth or rough surface …
The water absorption of aggregates is a key parameter in concrete mix design. As the adhered mortar of recycled aggregates present a long time of saturation (>24 h). A new approach of water absorption measurement was developed using hydrostatic weighing in order to observe the kinetic absorption of aggregates, and to …
Crushing waste concrete and using it directly as RAs has the disadvantages of high porosity and high water absorption. To achieve the reuse of resources, the researchers use microbial mineralization methods to further reinforce RAs. ... Study on Reducing Water Absorption of Recycled Aggregates (RAs) by Microbial …
Finally, it should be noted that recycled concrete aggregate has a water absorption coefficient seven times higher than natural aggregate, this has a negative impact through the demand for a ...
Crushing waste concrete and using it directly as RAs has the disadvantages of high porosity and high water absorption. To achieve the reuse of resources, the researchers use microbial mineralization methods to further reinforce RAs. In this paper, the effect of the microbial carbonic anhydrase mineralization method on the water …
However, all the studies concluded that the high water absorption of the recycled aggregates is one of the limiting factors in the quality of the recycle concrete obtained, as it has a negative impact on the consistency, the workability, and the mechanical and durability properties of the final product. ... This standard limits the …
The high water absorption of recycled concrete aggregates (RCA) can cause a significant reduction in the flow properties of cement-based materials in relation to mixes produced with natural aggregate. In order to compensate for this adverse effect, two extreme and simple approaches based on the water absorption of RCA in pure water …
Methods to determine the water absorption of recycled aggregates Water absorption measurements allow the calculation of the interconnected porosity of porous granular materials. ... The vacuum saturation method gives higher water absorption values than the standard method in both cases, but the difference is not statistically significant in the ...
In comparison to NC with 2.4 % water absorption and 5.4 % porosity, recycled concretes with RFCB achieve high water absorption ranging from 2.4 % to 3.0 % and larger porosity in the range of 5.3 %-8.7 %. More porous structure and high water absorption capacity of RFCB compared with NAF, could be the primary reason for this increment.
The adhered mortar on the recycled aggregates is highly porous which leads to high permeability and water absorption and has less density and resistance to fragmentation . The untreated recycled aggregates when mixed with concrete make it harsh and affect both the mechanical and durability properties of recycled aggregate …
The reuse of construction and demolition waste as a substitute for natural coarse aggregate in the production of recycled concrete has been widely used. In order to study the capillary water absorption performance of waterborne-polyurethane-modified recycled aggregate concrete (WPUMRC), the effects of different curing systems, …
Physical properties were influenced by the use of recycled concrete aggregate. Recycled concrete presented higher void index and, consequently, higher water absorption. This fact is due to the presence of attached mortar on RCA particles, which is responsible for the higher porosity of this material in relation to natural …
Recycled Concrete Aggregates are highly porous and may therefore absorb more water than natural aggregates. Several methods allow for the measurement of …
that when the water absorption of recycled aggregates and sand falls below 5%, the compressive strength may, at most, decrease by 15% (97.5% confidence) at any replacement level. ... an increase in porosity, the crushing index, high water absorption, and a weak interfacial transition zone [ 9] compared to materials. This …
Recycled aggregates show, however, high water absorption due to porosity. At saturation, water flows from the inside to the engaging cement paste matrix and at dryness the opposite process occurs. This water flow breaks the aggregate-cement paste bonds and increases the W/C ratio in the interfacial transition zone, this degrades …
Recycled aggregates from crushed concr ete have a higher percentage of water absorption than natural aggregates due to the mortar adhered to the aggregates ' surface, which increases the void ...
For recycled aggregate concrete at a low water/binder ratio of 0.255 prepared in this research, flaws in gravel are the main factor responsible for the decrease in mechanical properties, while flaws in attached mortar are the main factor responsible for the decrease in mechanical properties of recycled aggregate concrete at a high …
Recycled aggregate (RA) has a high water absorption rate. The quantity of water absorbed by RA in 15 min makes up more than 90% of the water absorbed in 24 h . ... The recycled concrete mix RCA-RFA has a higher water absorption capacity than NA because it is more porous. Despite this result, it is still within the acceptable limits …
The high water absorption of recycled concrete aggregates (RCA) can cause a significant reduction in the flow properties of cement-based materials in relation to mixes produced with natural aggregate.
There was about 20 % weight loss in grade 2; however, the loss in grade 4 was in the range of 20 to 40 %. The reasons for this high loss in volume from exposure to deicing agents are weak strength and high porosity of the recycled aggregate as indicated by high absorption. 4.1.2 Comparison Between Properties of the Aggregate and …
Besides, the water absorptions of two RCA, between 4.3 % and 10.86 %, are much higher than that of natural aggregates. Water absorption of RCA is strongly influenced by the particle size and ...
By collecting the used concrete and breaking it up, recycled concrete aggregate (RCA) is created (Fig. 1). This paper focuses on coarse RCA which is the …
