中華民國內政部建築研究所中華民國內政部建築研究所

一、研究緣起
在民國109年辦理的第11次全國科學技術會議中，「推動建築構件預製生產以減少碳排、縮短工期，並提升工作環境品質」被列為重要的討論議題。以往的研究已認知，在建築上將混凝土構件預鑄化有其優點與必要性，主要是預鑄廠製作的構件，品質容易掌握、產製速度快，且能避免工地現場澆置混凝土可能衍生的諸多缺點；尤其是預鑄工廠可利用完善的養護措施，來確保經減少水泥用量所製作的混凝土強度，得以符合需求，而有效達成節能減碳的目標。為縮短預鑄混凝土產製的時間，現行做法會以高溫蒸氣養護方式對預鑄混凝土進行養護，本研究主題即在探討養護方式對預鑄混凝土及其梁構件撓曲強度之影響。
二、研究方法及過程
本研究規劃兩種混凝土28天設計抗壓強度(280kgf/cm2、420kgf/cm2)、三種爐石粉取代水泥量(0%、30%、60%)及5種養護方式(常溫養護及預置1.5小時、3小時後50℃、70℃蒸氣養護6小時)等試驗變數進行抗壓強度試驗，之後從混凝土抗壓強度試驗結果中選出設計強度420kgf/cm2，爐石粉取代30%水泥量之混凝土製作梁試體，觀察常溫養護、預置3小時後50℃蒸氣養護梁試體的撓曲行為，並進行混凝土抗壓強度、滲透性及長度變化試驗，比較常溫養護與蒸氣養護對混凝土耐久性及體積穩定性的影響。
三、重要發現
抗壓強度試驗結果顯示，混凝土經蒸養後之抗壓強度隨爐石取代量增加而降低、隨齡期增長而提升，28天齡期前，常溫養護者之強度成展幅度大於蒸氣養護者，28天齡期後，經蒸養之含爐石粉混凝土強度仍有明顯成長。由滲透試驗結果可知，不論常溫養護或蒸氣養護，含30%爐石粉混凝土的滲透率較低，耐久性較佳。蒸氣養護混凝土早齡期的長度收縮量小於常溫養護者，56天齡期的長度收縮量則大於常溫養護者，體積穩定性較差。兩種養護方式梁試體於28天齡期的降伏或極限載重不相上下，56天及91天齡期時，常溫養護梁試體之降伏及極限載重高於蒸氣養護者，惟差距不大。
四、主要建議事項
根據養護方式對混凝土的抗壓強度、體積穩定性和耐久性，以及梁試體撓曲強度等性質影響的研究結果，提出下列具體建議。以下分別從立即可行建議及中長期建議加以列舉。
立即可行之建議—蒸氣養護時間對混凝土力學性質影響研究
主辦機關：內政部建築研究所
協辦機關：無
本研究以預置時間及蒸氣養護溫度為實驗變數進一步探討，蒸養時間則依成本及相關文獻建議固定為6小時，然而隨混凝土使用的卜作嵐材料種類及用量逐漸增加，有必要針對蒸養時效加以討論，找出可搭配不同卜作嵐材料添加量混凝土的蒸氣養護工法，將有助於提升預鑄混凝土技術及應用層面。
長期性建議—預鑄混凝土晚齡期工程性質研究
主辦機關：內政部建築研究所
協辦機關：無
本研究主要探討蒸氣養護對混凝土工程性質及梁試體撓曲強度的影響，56天及91齡期的試驗結果顯示，兩種養護混凝土的工程性質及梁試體撓曲強度接近，蒸氣養護者略差於常溫養護者，其中含爐石粉混凝土經蒸養後隨齡期增加其工程性質有逐漸改善的趨勢，若可進行更晚齡期的研究，如半年或1年，以瞭解卜作嵐材料於晚齡期時對預鑄混凝土及其構件各項性質之影響，研究成果對預鑄混凝土設計及應用具有重要的參考價值。

1.Purpose of Research
In the 11th National Science and Technology Conference held in 1991, “promoting the prefabrication of building components to reduce carbon emissions, shorten the construction period, and improve the quality of the working environment” was listed as an important topic for discussion. Previous studies have recognized that there are advantages and necessity to make concrete components in architecture, mainly components made by the factory, the quality is easy to grasp, the production speed is fast, and it can avoid the possibility of pouring concrete on the construction site. Many shortcomings; in particular, the precast concrete factory can use comprehensive maintenance measures to ensure that the strength of the concrete made by reducing the amount of cement can meet the demand, and effectively achieve the goal of energy saving and carbon reduction. In order to shorten the time required for the production and production of precast concrete, the current practice will cure the precast concrete by means of high-temperature steam curing. The subject of this research is to explore the influence of the curing method on the flexural strength of the precast concrete and its beam members.
2.Methodology and Process
This study plans two kinds of concrete 28-day design compressive strength (280kgf/cm2, 420kgf/cm2), three kinds of furnace stone powder to replace cement amount (0%, 30%, 60%), and five curing methods (normal temperature curing and preset 1.5 Hour, 3 hours, 50℃, 70℃ steam curing for 6 hours) and other test variables for compressive strength test, and then select the design strength 420kgf/cm2 from the concrete compressive strength test results, and the furnace stone powder replaces 30% of the cement content of the concrete. Observe the deflection behavior of the beam specimen after curing at room temperature and pre-positioning at 50℃ for 3 hours, and conduct the concrete compressive strength, permeability and length change tests to compare the effects of room temperature curing and steam curing on concrete durability and The influence of volume stability.
3.Important Findings
The compressive strength test results show that the compressive strength of concrete after steam curing decreases with the increase of furnace stone replacement amount and increases with age. Before 28 days of age, the strength of normal temperature curing is greater than that of steam curing. After 28 days of age, the strength of steam-cured concrete containing furnace stone powder still has significant growth. It can be seen from the results of the permeability test that, regardless of normal temperature curing or steam curing, the permeability of 30% furnace stone powder concrete is lower and the durability is better. The length shrinkage of steam-cured concrete at early age is less than that of normal temperature curing, and the length shrinkage of 56-day age is greater than that of normal temperature curing, and its volume stability is poor. The two curing methods have similar yield or ultimate load at 28 days of age. At 56 days and 91 days, the yield and ultimate load of beam specimens cured at room temperature are higher than those of steam curing, but the difference is not significant.
4.Major Recommedations
Immediate implementation:
Sponsor Agency: Architecture and Building Research Institute, Ministry of the Interior
Co-sponsor Agency: Architecture and Building Research Institute, Ministry of the Interior
This study uses the preset time and steam curing temperature as experimental variables to discuss. The steam curing time is fixed at 6 hours according to the cost and related literature recommendations. However, as the type and amount of Pozzolanic materials used in concrete increase gradually, it is necessary to focus on the steam curing time. Discussing and finding out a steam curing method that can be used with concrete with different dosages of Pozzolanic materials will help to improve the technology and application of concrete.
Long-term implementation:
Sponsor Agency: Architecture and Building Research Institute, Ministry of the Interior 
Co-sponsor Agency: Architecture and Building Research Institute, Ministry of the Interior
This study mainly discusses the effect of steam curing on the engineering properties of concrete and the flexural strength of beam specimens. The test results of 56 days and 91 days show that the engineering properties and flexural strength of beam specimens of the two cured concretes are similar, while the steam curing is slightly worse. In the case of room temperature curing, the engineering properties of concrete containing furnace stone powder after steam curing have a tendency to gradually improve with the increase of age. If it is possible to conduct a study at a later age, such as six months or one year, to understand the Pozzolanic reaction at late age. The research results have important reference value for the design and application of the concrete.