Study On The Control Of Construction Variability Of Cement Concrete Pavement

The cement concrete pavement is one of the main form of the highway in our country, but it grows slowly in the highway pavement in recent years. One reason that restricts the development of cement concrete pavement is the poor quality of construction and maintenance.As the construction process such as concrete mixing,transport,paving,vibration compacting and forming is not correct. After concrete paving,its strength is quite different from that under the laboratory test conditions.Therefore,the field construction concrete take on large variability. the curing environment changes with the atmospheric environment, which leads the strength development to be different from the indoor standard environment, therefore, strength of filed concrete slab varies from standard strength.Influence of process parameters on concrete pavement construction variability was researched from the perspective of construction process. The focus is the effect caused by construction process on the composition variation of concrete pavement surface, the design parameter's effect on the concrete pavement strength change were investigated mainly from the three aspects:the coarse aggregate content, water-cement ratio and cement composition. The results show that the water-cement ratio have larger influence on hardened concrete compressive strength and splitting tensile strength, and with the increase of cement content, water-cement ratio has less impact on compressive strength of hardened concrete. When the water-cement ratio is low,the cement concrete has a great impact on water absorption of hardened concrete,and the cement content has larger impact on the water absorption than the water-cement ratio.while they almost have no effect on the density of hardened concrete.The concrete strength influenced by temperature and humidity is mainly studied from the macroscopic scale. the effect of concrete strength under one or two factors is researched. The study has shown that the concrete strength is significantly increased by temperature, especially the low temperature;The effect of humidity is less than temperature;And then the comprehensive effect of temperature and humidity can be approximately regarded as the linear superposition of independent effect.