高剂量回收青混合物 (RAP) 在基于平衡设计的热现场回收中的性能
Lei Jiang1, Junan Shen2, Wei Wang3
1Jiangsu Technology Industrialization and Research Center of Ecological Road Engineering, Suzhou University of Science and Technology, Suzhou 215011, China.
Materials (Basel, Switzerland)
|May 11, 2024
概括
这项研究确定了高回收青路面 (RAP) 含量的热现场回收青混合物的最佳新粘合剂含量. 添加新的粘合剂可以提高裂抵抗力,但可以降低这些回收青混合物的蚀抵抗力.
科学领域:
- 土木工程 土木工程是指土木工程.
- 材料科学 材料科学 材料科学
- 铺路工程 铺路工程 铺路工程
背景情况:
- 热现场回收 (HIR) 是一种可持续的路面整治技术.
- 在HIR混合物中高回收青路面 (RAP) 含量在平衡和裂纹抵抗方面提出了挑战.
- 优化新添加的粘合剂对于在高RAP HIR混合物中实现期望的性能至关重要.
研究的目的:
- 为了确定高回收青路面 (RAP) 含量的热现场回收青混合物的最佳新粘合剂含量.
- 为了评估新的粘合剂含量对回收青混合物的化和裂变阻力的影响.
- 为高RAP HIR的应用提供实际的工程指导.
主要方法:
- 利用轮子跟踪测试来评估滑行性能.
- 采用半圆形曲试验来评估抗裂性能.
- 研究的回收青混合物含有80%和90%的RAP含量和不同的新粘合剂百分比 (RAP粘合剂总量的10%,20%,30%).
主要成果:
- 增加的新粘合剂含量降低了蚀阻力,但增强了裂纹阻力.
- 对于80%的RAP混合物,最佳的新结合剂含量为1.52% (5天老化) 和1.55% (10天老化).
- 对于90%的RAP混合物,最佳的新结合剂含量为1.23% (5天老化) 和1.28% (10天老化).
结论:
- 在高RAP HIR混合物中,通过优化新的粘合剂含量,可以实现平衡的和裂纹性能.
- 在不同的老化条件下,针对80%和90%的RAP混合物确定了特定的最佳新结合剂百分比.
- 这些发现为高RAP热现场回收青路面的实际工程应用提供了有价值的数据.
相关概念视频
01:14Design Example: Managing Concrete Workability
80
This example deals with managing the workability of concrete for a raft foundation project under hot weather conditions. Workability is crucial for ensuring the concrete is easy to place, compact, and finish. In this scenario, a slump test — a common method to measure the workability of fresh concrete — initially indicated low workability. This was attributed to the rapid water loss from the concrete mix, exacerbated by the high temperatures causing the course aggregates to heat up.
80
01:29Preplaced Aggregate Concrete
95
Preplaced aggregate concrete is ideal for construction environments that are not easily accessible. The process begins by properly wetting the gap-graded coarse aggregates to remove the dirt, then placing it in the form and compacting it. Voids are filled with a mortar mix pumped under pressure through slotted pipes. This mortar typically consists of Portland cement, pozzolan, fine aggregates, water, and a fluidizing aid. The pozzolan helps reduce bleeding and segregation while improving the...
95
01:24Design Example: Aggregate Gradation
93
The right type and quality of aggregates are crucial for concrete as they significantly influence its properties, mix proportions, and cost-effectiveness. If different sources are available for sand, the commonly used fine aggregate in concrete, the selection of sand is primarily based on its gradation.
The grading, or particle-size distribution, of sand is determined using sieve analysis, with standard sizes ranging from 150 μm to 10 mm (ASTM No. 100 sieve to 3⁄8 in. sieve). Sand is...
The grading, or particle-size distribution, of sand is determined using sieve analysis, with standard sizes ranging from 150 μm to 10 mm (ASTM No. 100 sieve to 3⁄8 in. sieve). Sand is...
93
01:20Hot Weather Concreting
64
Concreting at elevated temperatures accelerates the hydration process, leading to quicker setting but potentially reducing the long-term strength of the concrete structure. Additionally, low air humidity fosters rapid moisture loss from the concrete, resulting in reduced workability, pronounced plastic shrinkage, and a higher likelihood of crazing.
Mitigating the heat increase in concrete can be economically achieved by shading aggregate stockpiles to prevent heating from solar radiation,...
Mitigating the heat increase in concrete can be economically achieved by shading aggregate stockpiles to prevent heating from solar radiation,...
64
01:26Ready Mixed Concrete
85
Ready-mixed concrete, also known as pre-mixed concrete, is prepared in a centralized plant and then transported in trucks to construction sites where it is ready for placement. This type of concrete is categorized into central-mixed, truck-mixed (or transit-mixed), and shrink-mixed. Central-mixed concrete is entirely prepared at a plant and moved to the site in agitator trucks that rotate at a speed of 2 to 6 rpm. Truck-mixed concrete, on the other hand, has the ingredients batched at the plant...
85
01:30Mixing Concrete
113
Concrete mixing ensures a homogenous blend where aggregates are well-coated with cement paste. Concrete mixing is typically done using two main types of mixers: batch and continuous. Batch mixers handle one batch at a time, thoroughly combining materials before discharging and receiving the next batch. In contrast, continuous mixers receive a steady flow of ingredients, mixing them consistently and discharging without interruption. Within batch mixers, tilting drum mixers mix with internal...
113