The major difference between RA and ordinary aggregates is the amount of cement mortar attached on the surface of aggregate. When old concrete is crushed, a certain amount of mortar from the original cement mortar remains attaching to the stone particles in the RA, which forms a weak, porous and cracky layer (Tam, 2005, Tam, et al., 2005). …
In addition, drying shrinkage of mortar samples and the plastic shrinkage cracking behavior of concrete sample s made of the investigated fine aggregate types were also explored during this parametric study. 25-30% reduction of the mortar density was recorded with using lightweight brick industrial waste as fine aggregate with reduction of the ...
Mix ingredients typically consist of lime, cement, aggregate, water, and possibly pigments. The relative ratio of lime to cement to aggregate will determine the compressive strength, workability, bonding strength, joint texture, elasticity, and color characteristics of the mortar. a.Cement: Portland cement has been used since the mid-1800s.
In order to improve the recycled concrete aggregate quality, researchers have adopted two main pathways: (1) removal of adhered mortar from aggregate …
One useful advantage of the mortar aggregate ratio test, compared to mortar compression testing, is its speed. Technicians can determine the ratio using the procedure in hours. Compression tests using mortar cubes or cylinders can take several weeks to perform since the samples must be cured, typically in three, seven, or 28 days.
One top-surface retarder product is Surface Deactivator by Brickform, which provides ten exposure depths, from a simulated light acid etch or sand blast finish up to full exposure of 1 ½" aggregate. Surface Deactivator offers …
There are two potential solutions to this problem (Hendriks and Pietersen, 2000): (i) substitute gravel by using secondary aggregate and increase the …
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 …
With the various techniques for removing paste from the RCA, a combination of three enhancement processes were developed for the effective removal …
The water absorption values ranged from 1.25% to 2.67%, indicating that POFA-FA assists in the cement hydration process and also serves as a filler. As a result, the material's density is very high, leading to fewer voids formed, thus reducing the trapped water, which significantly affects the mortar's strength.
The interfacial transition zone hardness at the aggregate-mortar interface is 53.94, 34.21, and 44.08 % of bulk concrete for control concrete, recycled coarse aggregate-1 concrete, and recycled ...
The properties of cement concrete using waste materials—namely, recycled cement mortar, fly ash–slag, and recycled concrete aggregate—are presented. A treatment process for waste materials ...
A similar behavior was reported by Souza [7]. The pozzolanic activity of the PPR associated with the filler effect caused by the particle size of the waste, which is finer than the cement (Figure ...
Method: A mechanical abrasion process is used to reduce the amount of mortar in different degrees from the recycled aggregates that will be used to replace a 40 % of …
Because the production of aggregates for mortar and concrete is no longer sustainable, many attempts have been made to replace natural aggregates (NA) with recycled aggregates (RA) sourced from factories, recycling centers, and human activities such as construction and demolition works (C&D). ... S.H., Tembalang, Semarang, 50275, …
The presence of old cementitious mortar in recycled concrete aggregates (RCA) has been reported to be one of the main factors contributing to a lowering of the …
ingredient other than cement, aggregate, or water that is added to change physical or chemical characteristics. ... efflorescence. white crystalline deposit that appears on surface of concrete or mortar. slump test. a test to measure the consistency of concrete. consolidation. process of removing air pockets and forcing concrete into voids in ...
Performance of recycled concrete aggregates developed ... [2–4]. The removal of mortar is an eective method for improving RCA's quality [17, 4, 18]). Although mechanically treated RCA can con- ... In the case of cement matrix, the decarbonation process causes severe microcracking at temperatures between 600 and 800 °C [33]. RCA is degraded by
DOI: 10.3151/jact.21.477 Corpus ID: 259566586; Effect of Original Mix Proportion on Rapid Removing of Attached Mortar for Recycled Concrete Aggregate Through a Freeze-thaw Approach
A cement-based mortar incorporating a mineral oil addition of up to 10% of the aggregates mass was used. The results indicated that the mixing method has only a small effect on the fresh and ...
Li X (2009) Recycling and reuse of waste concrete in China. Part II. Structural behaviour of recycled aggregate concrete and engineering applications. Resour Conserv Recycl 53:107–112. Article Google Scholar Liu S, Shen P, Xuan D, Li L, Sojobi A, Zhan B, Poon CS (2021) A comparison of liquid-solid and gas-solid accelerated …
For the ''large aggregate'' (L) concrete mix, the maximum aggregate size was larger than 19.1 mm, while the ''small aggregate'' (S) mix used a maximum aggregate size of 12.7 mm. Type I Portland cement was used in all eight mixtures. The fine aggregate used for both the mortar and concrete mixtures was Colorado River sand from ...
Researchers have adopted 2 main pathways to produce recycled concrete aggregate of high quality: (1) removal of adhered old cement mortar from the aggregate grains; and (2) fortification of attached cement mortar to make it stronger, less porous, …
In order to improve the recycled concrete aggregate quality, researchers have adopted two main pathways: (1) removal of adhered mortar from aggregate grains and utilisation of the separated mortar, and (2) fortification of residual mortar to make it stronger, less permeable and hydrophobic.
The effect of recycled fine aggregate (RFA) on the properties of mortar is investigated in this present research work. Mortar specimens are prepared with three different water/cement ratios (0.4 ...
The silica sand waste generated from the sandblasting process of coating removal during ship maintenance and repair poses various ... friction between the Cement and aggregate particles, making pouring, shaping, and finishing the concrete easier, resulting in a better ... SEM, and XRF. The concrete mortar produced with the addition …
At concentration of 0.5 M, the mortar removal was 2 times higher for 10 mm size recycled concrete aggregate compared to 20 mm, but at higher HCl concentrations, the mortar removal rate was only 1% higher, indicating that for bigger size recycled concrete aggregate, higher molar concentrations of HCl may be needed for effective …
Due to the involvement of multiple types of concrete and mortar in the above process, in order to prevent confusion of different types of concrete or mortar in subsequent experimental processes, various types of concrete and mortar that will be used are summarized in Table 1, including recycled aggregate matrix concrete, …
The fundamental reason for the poor performance of recycled aggregate (RA) and recycled aggregate concrete (RAC) is the attached mortar, which severely restricts the application of RA and RAC. This research proposes an innovative method for the modification of RA: using the freeze–thaw cycle (FTC) to remove the attached …
Using Acid To Dissolve Mortar. Mortar, the sticky adhesive used to hold bricks together in construction, can be a challenge to remove from brick surfaces.However, it can be easily dissolved with acid due to …