Key Technologies for Quality Control of Large Volume Concrete for Prefabricated Piers and Abutments of Cross Sea Bridges—Taking Xiamen Xiang'an Bridge as an Example
In order to improve the durability of large pier and abutment concrete structures and prevent concrete cracking,based on the Xiamen Xiang'an Bridge project,this paper analyzed and studied the quality control technical measures of prefabricated pier and abutment large volume marine concrete for cross sea bridges from the aspects of concrete mix proportion optimization design and temperature control.In terms of mix proportion optimization design,the characteristics of marine concrete and large volume concrete were comprehensively considered,with durability as the core and balanced development of various performance indicators as the goal.Following the principle of equal emphasis on resistance to chloride ion penetration and crack resistance,low heat silicate slurry,moderate water cement ratio,high dosage high-quality fly ash and slag powder admixture,and high-performance water reducer were mainly used.Through calculation,trial mixing,testing,and optimization adjustment,the concrete mix proportion that met the requirements and had the best comprehensive performance were selected as the quality control measure.In terms of temperature control,the characteristics of large volume concrete,such as the large amount of hydration heat generated by cement during the initial pouring stage,susceptibility to external temperature changes,and significant volume shrinkage deformation after concrete hardening,were comprehensively considered.The main measures taken included cooling the raw materials,strictly controlling the temperature of concrete entering the mold,optimizing the pouring process,strengthening temperature control after pouring,and paying attention to maintenance work to control temperature and crack prevention.The results of indoor tests and physical inspections show that,the technical indicators related to the workability,mechanical properties,durability,compactness,crack resistance,and volume stability of concrete meet the design and specification requirements.Practice has proved that the optimization design of concrete mix proportion and temperature control measures for large prefabricated piers and abutments are feasible.
cross-sea bridgelarge prefabricated piers and abutmentslarge volume concreteconcrete mix proportiontemperature control and crack prevention measures
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