浅谈小型机具摊铺水泥混凝土路面裂缝分析及预防措施

提高水泥混凝土路面质量的一个重要措施,是预防产生裂缝。造成混凝土板面产生裂缝的原因,归结起来无非是设计考虑不周或施工质量问题。弄清水泥混凝土板产生裂缝的原因,并采取有效的措施预防裂缝的产生,对延长路面的使用寿命,保证道路畅通,具有重要的意义。

水泥混凝土路面抗滑构造施工与养生

高速公路的水泥混凝土路面对抗滑构造的要求,一是雨天行车横向排水,降雨和暴雨时,车轮和路面之间尽量紧密贴合,使路面不产生水膜,防止高速行驶的车辆发生漂滑现象;二是它提供潮湿路面的侧向摩擦系数。因此二级抗滑构造为雨天高速行驶的车辆提供了安全技术措施。现就施工的滑模摊铺混凝土路面的抗滑构造施工方法作一阐述。

采用树脂类胶粘剂修补水泥混凝土路面裂缝

介绍采用环氧树脂类材料修补水泥混凝土路而裂缝的方法，指出了材料配合比和施工中应注意事项。

共振碎石化技术在公路水泥混凝土路面再生利用中的应用

共振碎石化技术是公路水泥混凝土路面再生利用的一种新技术。该技术具有能够彻底消除路面反射裂纹,使用年限长,工程造价低,施工程序简便高效,交通影响小,环保等优点。是公路水泥混凝土路面再生利用的最佳方法。文章根据我国公路水泥混凝土路面的实际情况,如何使用共振碎石化技术,对旧水泥混凝土路面再生利用的理论和具体施工技术作了详细的介绍。

水泥路面破坏的原因及其防治

水泥混凝土路面因其整体性能好、强度高、使用寿命长、维护费用低等优点，在公路和城市道路建设中广泛采用。水泥混凝土路面存在一些缺点和不足主要的是路面普遍存在裂缝和断板问题。混凝土板一旦产生断板，其它病害就会伴随着发生，如水泥、错台、脱空、裂缝破碎、拱起、裂缝延长、跳车等破坏。对水泥混凝土路面产生破坏的主要原因做分析，然后就防治措施做相应的探讨和阐述。

Strength of copolymer grouting material based on orthogonal experiment

Using the orthogonal experimental design method involving three factors and three levels, the flexural strength and the compressive strength of copolymer grouting material were studied with different compositions of water-cement ratio （mass fraction of water to cement）, epoxy resin content, and waterborne epoxy curing agent content. By orthogonal range and variance analysis, the orders of three factors to influence the strength, the significance levels of different factors, and the optimized compound ratio scheme of copolymer grouting material mixture at different curing ages were determined. An empirical relationship among the strength of copolymer grouting material, the water-cement ratio, the epoxy resin content, and the waterborne epoxy curing agent content was established by multivariate regression analysis. The results indicate that water-cement ratio is the most principal and significant influencing factor on the strength. Epoxy resin content and waterbome epoxy curing agent content also have a significant influence on the strength. But epoxy resin content has a greater influence on the 7-day and 28-day flexural strength, and waterborne epoxy curing agent content has a greater influence on the 3-day flexural strength and the compressive strength. The copolymer grouting material with water-cement ratio of 0.4, epoxy resin content of 8% （mass fraction） and waterbome epoxy curing agent content of 2% （mass fraction） is the best one for repairing of cement concrete pavement. The flexural strength and the compressive strength have good correlation, and the ratio of compressive strength to flexural strength is between 1.0 and 3.3.

Characterizing properties of magnesium oxychloride cement concrete pavement

The performance of magnesium oxychloride cement concrete(MOCC)in road engineering in the arid region in northwest China was investigated over a two-year period.Two categories of MOCC pavement,light-burnt magnesia concrete road(Road-L)and dolomite concrete road(Road-D),were prepared with light-burnt magnesia and a mixture of light-burnt magnesia and caustic dolomite(1:3 by mass),respectively.Variations in the properties of the MOCC pavement,such as compressive and flexural strength,mineralogical phase,and microstructure,after being exposed to two rainy seasons in the field were monitored.The compressive strength of the cored samples were conducted after being aged for 28 d,and the compressive and flexural strength were tested at ages of 1,2,3,28,90,180,270,360 and 720 d.The mineralogical phase and microstructure of the pavement were also analyzed by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results demonstrate that MOCC pavement obtained desirable compressive and flexural strengths after curing for 3 d for Road-L and 28 d for Road-D.Both of the compressive and flexural strength of Road-L and Road-D decreased slightly after experiencing two rainy seasons,with the major hydration products being 5Mg(OH)2 MgCl28H2O(Phase 5)and 3Mg(OH)2 MgCl28H2O(Phase 3).The decomposition of Phase 5 is mainly responsible for reducing the mechanical strength of the MOCC pavement.

Constraints in Using Manufactured Sands in Concrete Pavements in Australia

Due to the shortages of natural sands along the east coast of Australia in particular and the need to fully utilise fines produced in quarry operations, progress has been made in utilising blends of manufactured sands and natural sands in concrete pavements. This paper documents some of the constraints in utilising larger proportions of manufactured sands in concrete pavements. These constraints are mainly caused by the current level of knowledge regarding the impact of manufactured sands on skid and abrasion resistance of concrete pavements. This paper presents a brief review of literature on this subject in the USA, France and UK. It also briefly documents work recently carried out in Australia by CCAA （Cement Concrete and Aggregates Australia）, referring to the skid and abrasion resistance of concrete pavements using manufactured sands. The paper concludes that there is no relationship between the free silica content and the skid resistance. With regard to the abrasion resistance, it is rather the curing conditions and the compressive strength that are more important in achieving good results.

Curling of New Concrete Pavement and Long-Term Performance

Curling results from the temperature differential across the concrete slab thickness and may induce undue stresses in newly placed slab. This study deals with the finite element （FE） analysis of curling, curling stresses, field measurement of curling on a newly built jointed plain concrete pavement, and comparison of its long-term performance using both Mechanistic-Empirical Pavement Design Guide （MEPDG） and HIPERPAVII software. The FE analysis was performed with a software program, ANSYS. The test section was modeled as a three-layer system with 300 mm concrete slab, 100 mm treated drainable base, and 150 mm lime-treated subgrade. All layers were assumed to be linear elastic. Temperature data was collected at five different depth locations across the concrete slab with digital data loggers. Curling was measured on five different days with a simple setup. The effect of temperature nonlinearities across the slab thickness was also examined. The results show that both upward and downward curling increase as the temperature differential increases. The maximum stress resulting from the combined effect of curling and traffic loading due to positive temperature differential is higher than that due to the negative temperature differential of the same magnitude. Since temperature differential has a significant influence on curling, both curling and curling stresses can be mitigated at an early age with temperature control, namely via enhanced curing. Both MEPDG and HIPERPAVII showed approximately the same performance for the PCC thickness ranging from 215 mm to 300 mm for this project. Performance prediction from HIPERPAVII is very sensitive to the change in PCC thickness less than 230 mm whereas MEPDG prediction is not as sensitive to the thickness change as with HIPERPAV 1I.