Research On Temperature-control Technology Of Hydraulic Pump-Delivery-Concrete For Water Conservancy Structures In Jiangsu Province

During last few years, application of pumping concrete into hydraulic construction has been more and more popular in Jiangsu Province. Pumping concrete brings convenience into construction, but bring more concrete cracks during construction, and some of these are serious, however, higher requirement of concrete exterior quality has been required in hydraulic construction. In such a context, a scientific research project——"Method to Prevent Pump-concreting for Water Conservancy Structures from Crack" has been set-up and funded by Jiangsu Provincial Water Conservancy Bureau, in order to modify the shortage of temperature control in design and construct, and reduce the possible of appearance of crack by special research in this fieldFrom the basic theory of temperature and temperature stress, the heat balance equation of unsteady temperature and finite element method based, systematic introduce temperature stress calculation method and the theoretical found of concrete cracks, focus on the theory of common anti-crack reinforcement rebar,pipe cooling,calculation of the temperature control of expansive concrete.In order to solve the difficulty in calculating temperature control, "Temperature Stress Analysis System for Pouring Block" has been developed on the base of these theories. The elaborate mathematics model has been applied in this software, which can simulate the whole process of concrete pouring block during construction, reveal the comprehensive relationship among those factors, and predict whether the cracks appeared. If the result can't satisfy the request of anti-crack, optional measures of temperature control can be taken until the requirements are met.First, this thesis introduce how to calculate temperature control of some construction which had already used common adjustment(application of cooling pipe, reduce cement consumption, application of arch pier-wall) by this software. Then compute actual on-going construction, and adjust the construction scheme on the base of the computation result.Then, after sum up several results of usual pump concrete mix ratio in Jiangsu Province, the measures of temperature control during design and construction have been proposed.At last, the conclusion is——it is possible to satisfy the temperature control and reduce the appearance of crack by use of "system" to calculate and optimization scheme during the design period.