Research To Ascertain Concrete Strength Of Pretensioned Spun Concrete Piles By Rebound Method

According to the developing conditions of ascertaining the concrete strongths of pretensioned spun concrete piles,the article worked out a method to ascertain concrete strengths of pretensioned spun concrete piles by rebound.This method is very important to the production and using of pretensioned spun concrete piles.In this paper,by testing rebound value of pretensioned spun concrete piles and compressiving strength on each of cubic specimens cured under the same condition, the article have established a regressive equation about relationship "reound-strength" of the specimens:y=-0.0575x~2+8.2927x-206.92.And the same time,through the testing on the strength of core drilled from the same pretensioned spun concrete piles,this article did research on the influence of pretensioned spun concrete piles' centrifugal production.Comparing these testing results,we found correlative factor,and then got a new equation which satisfies to ascertain the concrete strengths of pretensioned spun concrete piles bodies practically: y=-0.0616 x~2+8.8898x-221.82.For the more,the article analyzed the influence factors about this equation,and shew that with the thickness and the external diameter of pretensioned spun concrete piles bigger,the errors are smaller.