碾压混凝土非绝热温升试验及分析

依托某工程,进行碾压混凝土在非绝热状态下的温度试验,并获得实测数据,对实测数据进行了温度场的反演计算,并将计算值与实测值进行了比较,分析了反演结果的合理性,以供类似工程参考。     

碾压混凝土的渗透及溶蚀耐久性的计算

本文对碾压混凝土的溶蚀和渗透耐久性进行了阐述，给出了碾压混凝土临界水力梯度及渗透、溶蚀耐久性的计算公式，并结合工程实际进行了计算。     

旧水泥混凝土路面加铺沥青混凝土浅析

简单介绍了旧水泥混凝土路面使用现状及改善行车条件的必要性,分析了在旧水泥混凝土路面上加铺沥青的可行性,具体阐述了加铺沥青前的技术准备和对路面的技术处理及病害预防措施,以指导实践。     

旧水泥混凝土路面碎石化处理技术

介绍了旧水泥混凝土路面碎石化处理技术的基本原理、适用情况、主要措施,以及碎石化处理的技术要求和质量控制评价等,指出其应用于破损严重的水泥混凝土路面改建具有重要意义。     

隧道路面碾压混凝土高强化研究

为开发高性能隧道碾压混凝土路面,通过正交设计,研究水胶比、水泥用量、硅灰用量、减水剂种类及掺量对碾压混凝土抗压强度的影响规律,以高抗压强度为考核指标,进行了高强化的试验研究,经配合比优化设计,优选了碾压混凝土的工艺参数,结果满足C50强度等级的设计要求,外加剂的对比研究发现,聚羧酸高性能减水剂比萘系和氯基磺酸盐系减水剂...     

Shrinkage properties of compacted sand concrete used in pavements

Compacted sand concrete is being researched for potential usage in road construction because of shortage in gravel resources in many countries. However, one of the problems for this material with such application is shrinkage cracking. This paper presents the results of the unrestrained shrinkage test performed on three different compacted sand concrete mixes. Two existing shrinkage prediction models, namely the ACI 209 and the CEB 90, were used to fit the measured shrinkage data. The CEB 90 model with an application of a correction factor was found to perform well with compacted sand concrete. Based on the results of the shrinkage tests, joint spacing between compacted sand concrete slabs was calculated.     

Comparison of test specimen preparation techniques for pervious concrete pavements

The objective of this study was to evaluate different pervious concrete test specimen preparation techniques in an effort to produce specimens having properties similar to in-place pervious concrete pavement. Cylinders and slabs were cast using pervious concrete from three different paving projects using different procedures. The comparisons of cast specimens to pavement cores were based on infiltration rate, density, and porosity. Of the cylinder consolidation procedures tested, the standard Proctor hammer provided the least variability of results and yielded properties similar to the in-place pavement. However, 600 mm square slabs were even more consistent with the in-place pavement density and porosity.     

Asphaltic concrete overlays on surface-treated pavements with lateritic gravel bases

The design and performance of asphaltic concrete overlays for surface-treated pavements with lateritic gravel bases and subbases using the results of Benkelman beam deflection measurements are discussed. It is found that failure to consider pavement distress factors, local materials and environmental conditions in design are inadequate and early signs of distress are exhibited. It is concluded that the high percentage of unpredictable generated traffic is an important contributing factor to performance. An assessment of stress interaction between the existing surface-treated pavement with granular bases and subbases and the asphaltic concrete overlay needs to be considered in the design process. An appropriate approach would be to consider the overlay design as a new asphaltic concrete-surfaced pavement with granular base and subbase.     

Sealing system selection for jointed concrete pavements – A review

Concrete pavement joints are cracks intentionally formed in the pavement to accommodate expansion and contraction due to temperature changes. Today, 98% of the agencies building and maintaining concrete roadways, and 100% of the agencies building and maintaining concrete airport pavements in the United States require the sealing of these joints for new pavements. There are two major reasons for sealing rigid pavement joints. The first is to reduce the amount of water infiltrating the pavement structure, which results in slab erosion and loss of support. The second reason is to minimize the entry of incompressible materials into the joint reservoir, resulting in point loading when slabs expand under hot temperatures and subsequent joint spalling damage. Another reason for sealing rigid pavement joints is to reduce the potential for dowel bar corrosion by reducing entrance of de-icing chemicals. The proper sealing and maintenance of concrete pavement joints thus seems to be essential for the overall performance of the rigid concrete pavement. This paper seeks to find out the factors that affect sealant life and performance and how to mitigate these to improve performance and reasonably extend sealant and thereby pavement life.     

Mix proportion of high-strength,roller-compacted,latex-modified rapid-set concrete for rapid road repair

In this study, we optimized a blend of high-strength, roller-compacted, latex-modified rapid-set concrete (RCLMC) that can be re-opened to traffic after 4 h. To this end, we tested several variables in laboratory experiments, including hardening acceleration agents, cement type, latex addition, and CSA admixture ratios. The target compressive strength was 21 MPa after 4 h. A mixture of Type III cement to CSA admixture at 235:165 kg/m³ (400 kg/m³ total binder) and 23.5 kg/m³ latex (10% of the cement weight) achieved the target compressive strength and was the most economically efficient.     

沥青混凝土拌合机及配套设备在施工中的应用

通过对德基DG4000型沥青拌合机在高速公路路面施工中的应用情况进行分析,提出了该大型拌合机的配套施工机械的最优组合,结果表明,DG4000型拌合机及配套施工机械在路面施工中不仅能保证施工质量,加快施工进度,并能取得良好的经济效益和社会效益。     

蒸养混凝土的抗盐冻剥蚀性能

研究了在冻融循环和除冰盐共同作用下,蒸养混凝土的抗盐冻剥蚀性能及其影响因素,并探讨了相应的防治技术措施。     

影响沥青混凝土路面平整度的因素及应对措施

结合沥青混凝土路面施工实践,对影响沥青路面平整度的原因从五个方面分别进行了分析,并提出相应的解决方案和预防措施,从而保证路面平整度,提高路面工程质量。     

沥青混凝土路面施工机械选择及质量控制

指出在高速公路沥青混凝土路面施工过程中,施工机械的配置组合、施工过程的质量控制是关键,对大型拌合机及其配套机械在高速公路路面施工中的应用情况进行了分析介绍,并对施工中的关键问题提出了相应的质量控制措施。     

沥青混凝土路面常见病害成因及处治措施

通过对沥青混凝土路面常见病害进行分析,揭示沥青混凝土路面病害产生的原因,提出沥青混凝土路面病害的预防及处治措施,以提高路面使用性能,延长沥青道路寿命。     

Experimental study and field application of calcium sulfoaluminate cement for rapid repair of concrete pavements

The fast-track repair of deteriorated concrete pavement requires materials that can be placed, cured, and opened to the traffic in a short period. Type III cement and Calcium Sulfoaluminate (CSA) cement are the most commonly used fast-setting hydraulic cement (FSHC). In this study, the properties of Type III and CSA cement concrete, including compressive strength, coefficient of thermal expansion (CTE) and shrinkage were evaluated. The test results indicate that compressive strength of FSHC concrete increased rapidly at the early age. CSA cement concrete had higher early-age and long term strength. The shrinkage of CSA cement concrete was lower than that of Type III cement concrete. Both CSA and Type III cement concrete had similar CTE values. Based on the laboratory results, the CSA cement was selected as the partial-depth rapid repair material for a distressed continuously reinforced concrete pavement. The data collected during and after the repair show that the CSA cement concrete had good short-term and long-term performances and, therefore, was suitable for the rapid repair of concrete pavement.     

浅议水稳厂拌式碾压混凝土施工质量检查控制方法

以云梧高速公路刚性碾压混凝土基层的建设为基础,统计分析其施工质量检测结果,结合其施工经验,提出了针对水稳厂拌式碾压混凝土施工质量检查的控制方法。     

Fatigue behaviour of recycled tyre rubber-filled concrete and its implications in the design of rigid pavements

This paper presents the results of fatigue bending tests on prismatic samples of recycled tyre rubber-filled concrete (RRFC) with different volumetric fractions (VF) of rubber (0%, 3.5% and 5%) after a long term exposition to natural weathering in Madrid (Spain) (one year ageing). From these experimental results, an analytical model based on classical Westergaard well known equations has been developed to calculate the minimum thickness of RRFC for rigid pavements subjected to high density traffic, in order to obtain a durability of these rigid pavements of 10⁶ cycles of 13 tons (127 kN) axle load. In this investigation any value of the modulus of subgrade reaction for rigid pavement design have been considered.     

无砂混凝土抗冻性研究

通过正交试验设计时无砂混凝土抗冻性的影响因素进行分析。采用比较先进的快冻法评价无砂混凝土的抗冻性,实验结果袁明：集灰比影响非常显著。集料粒级次之。     

自密实混凝土的抗冻融性能研究

自密实混凝土是一种具有高流动性,且具有持久稳定性的混凝土。由于这类混凝土只是近年来才被广泛认可,所以关于硬化后的自密实混凝土耐久性研究非常有限,尤其是在寒冷气候条件下,为此,我们对自密实混凝土抗冻融循环的性能进行了实验室和现场试验,证明了可以生产出具有抗冻融的自密实混凝土。同时我们发现,自密实混凝土的耐久性取决于很多因素,其中包括高效减水剂和引气剂的类型等。从本文我们可以发现,高效减水剂和引气剂之间配比不同,自密实混凝土的气孔质量也不同,在自密实混凝土中,相比传统的自然松香型引气剂,使用合成型的引气剂能形成更好的气孔结构。当混凝土气泡比表面积小于24mm^2/mm^3,间隔系数大于0.20mm时,也能生产出抗冻融循环的自密实混凝土。