Strength Of Concrete In Construction Inspection And Assessment Of Research

IntroductionTo strengthen the supervision to the quality of the building project, A new policy will be carried out in our country. Under this policy, checking will be separated from ascertain and the ascertain will be strengthened, the measurment will be perfected and the process will be controlled. The national standardGB 50204-2002 was newly revised, in which it is stated to inspect the strength of the structural concrete.The sample cured under the standard curing condition is different to the structure on the size, casting and the curing condition(temperature and the humidity,etc). So, the strength of the sample under the standard curing condition is different to that of the actural structure. The sample cured under the same curing condition has the difference on the size with the structure. There is inaccuracy to the strength got by the testmethods of the non-destructive test and the mini-destructive. The strength of the sample taken from the structure is thought to the nearest to the strength of the constructural concrete. While the structure is damaged when taken samples from it.In GBJ81-85, it is suggested to use the sample cured under the same conditon to the structure when the strength of the structural concrete is tested, while the relation between the samples cured under the standard condition and that under the same condition to the structure is not given out in it. In GBJ 107-87 and CECS40 : 92, the strength of the sample under the same curing condition is used as a controling datum in the period of construction and the strength of the sample cured under the standard condition as a datum to test the quality of the concrete which is not pointed out the materal or the element made of the materal. In , it is definituded that the strength of the sample cured under the standard condition is used to test the strength of the structral concrete.In American code ACI318-89, the sample cured under the same condition to the structure is used to check if the curing condition of the structure is appropriate, and the difference between the standard curing room and the actural structure is considered. In (MC90), the formula is given out to calculate the increasing of the concrete strength tothe temperature and the curing age.In this research, the strength of the sample cured under the standard condition, the sample cured under the same condition to the structure and that of the sample taken from the structure is studied by different grades pre-casted concrete on different curing age. The relations of these strength are given out. With the temperature recordered each day, the experimental data are analyzed and on the base of the given production, the appropriate test methods to the structural concrete are given out.The Concrete Strength TestIn this test, the concrete walls and samples are designed. The samples are cured under the standard condition and the same condition to the walls. Three are two factories' products are used in the experiment. The concrete grades are C20~C80 (A)and C20~C60(B). The curing age of the concrete walls and the samples cured under the same condition are designed to be 14d,28d,60d and 90d, while the samples cured under the standard condition are designed to be 14dand28d.There are 12 walls and 252 groups of samples in the experiment. The walls are casted by the internal concrete vibrator and the samples cured under the same condition are casted b...