台灣混凝土變形預測模式B4-TW建置（二）：乾縮、自體收縮與總收縮

Establishment of B4-TW Prediction Model for Concrete Deformation in Taiwan (II): Drying Shrinkage, Autogenous Shrinkage and Total Shrinkage

秦維邑(Wei-Yi Chin) ； 陳振川(Jenn-Chuan Chern)

《結構工程》 33卷3期 (2018/09) Pp. 65-86

https://doi.org/10.6849/SE.201809_33(3).0004

摘要

目前台灣之混凝土工程設計規範之混凝土收縮計算並未有明確公式，未能和混凝土材料之性質連結。致其計算常使用國外之美國ACI、AASHTO，歐洲CEB-FIP、RILEM等預測公式。混凝土變形問題仍因牽涉世界各地區氣候環境、組成材料、配比及施工實務等，而有所差異性。台灣混凝土使用之粒料性質堅實度較為不足，配比設計時為追求強度達標，有使用高漿體量、高水泥量、低水灰比、低粒料量／水泥量比等特性，上述之本土化特性非使用國外預測公式可掌握，故台灣著實需要發展良好之本土化混凝土收縮預測公式。經評估現有國內外混凝土收縮預測規範，本文選用美國西北大學Bazant等人發展於2015年提出之Model B4收縮預測公式為基礎。針對上述之台灣混凝土特性進行本土化的修正，並考慮台灣常用之砂岩粒料造成之影響，找出適用於台灣之粒料修正參數。本文亦針對含有礦物摻料之混凝土進行摻料影響之修正，選用FIB2000作為自體收縮時間成長曲線，並修正Model B4之礦物摻料參數表格，建立適合台灣使用之內含自體收縮項目的Model B4-TW收縮預測公式。結果顯示，進行本土化修正後之Model B4-TW收縮預測公式，在預測台灣普通混凝土或含有礦物摻料混凝土收縮時，均有極優表現，可發展為適用台灣本土之混凝土收縮預測公式。

關鍵字

混凝土 ； 長期變形 ； 收縮 ； 高爐石粉 ； 飛灰 ； 資料庫

並列摘要

At present, there is no definite formula for concrete shrinkage calculation in the concrete engineering design code of Taiwan, which cannot link with the nature of local concrete material. Most engineers in Taiwan often use the formula of American Concrete Institution (ACI), the American Association of State Highway and Transportation Officials (AASHTO), and European CEB-FIP and RILEM codes. The problem of concrete deformation is still different because it involves the climate environment, mix design, proportion and construction practice in different areas. The aggregate quality of the concrete used in Taiwan is poor, and the mix is designed to achieve the strength with the use of high paste volume, high cement content, low water/cement ratio, low aggregate/cement ratio and other characteristics. The localization characteristics described above cannot be mastered by foreign prediction formula, so Taiwan really needs to develop a good local concrete shrinkage prediction formula. Based on the evaluation of the existing domestic and foreign concrete shrinkage prediction formulae, this paper chooses the model B4 shrinkage prediction formula developed in 2015 by Bazant of Northwestern University. With regard to the local characteristics of the concrete in Taiwan, and the effect of the commonly used sandstone aggregate in Taiwan, the modified parameters of the aggregate are found. In this paper, the influence of concrete containing mineral admixture is modified: the FIB2000 is selected as autogenous shrinkage time growth curve; and the mineral admixture parameter table of model B4 is modified. These local modifications led to the establishment of the Model B4-TW. The results show that the model B4-TW shrinkage prediction formula, which included autogenous shrinkage, after localization correction has excellent performance in predicting the shrinkage of normal concrete or concrete containing mineral admixture in Taiwan, and can be developed as a concrete shrinkage prediction formula for Taiwan.

並列關鍵字

concrete ； long-term deformation ； shrinkage ； blast-furnace slag cement ； fly ash ； dataset