石油廢觸媒之反應活性及對水泥質材料性質之影響

吳榮修(Wu Jung-Hsiu)

指導教授 ： 許貫中

國立臺灣師範大學/理學院/化學系/碩士(2001年)

摘要

石油廢觸媒(Epcat)來自於石油裂解廠的廢觸媒，主要由Al2O3及SiO2所組成，且具有部份非結晶相和波索蘭材料之特性，預期應具波索蘭活性。
本實驗分為三部分進行。第一部份將Epcat添加至水泥漿及砂漿中觀察抗壓強度變化。在不同實驗配比下(水膠比0.2、0.25、0.3, Epcat取代水泥量為0、5％、10％、15％)，添加強塑劑MTP維持各配比之工作度，養護後量測試體3、7、28天的抗壓強度。實驗結果顯示，Epcat能提升水泥漿及砂漿的強度，且以砂漿增加的幅度為大。例如水膠比0.3且5~15%Epcat取代的配比，在3~28天齡期，砂漿強度比控制組增加13％∼41％，而水泥漿強度僅增加1%∼14％。
而當水膠比從0.3降至0.25，或Epcat取代量增加時，抗壓強度增加效應更明顯。砂漿強度增加的原因不僅僅是Epcat增加水泥漿的強度，更強化了骨材與水泥漿間鍵結。不過當水膠比降至0.2時，因維持流度而添加過多MTP，使整個強度效應變得不明顯。
第二部分利用熱示差掃描儀（DSC）來分析探討Epcat之波索蘭活性。實驗方面拌製純水泥漿體與含5~30 %廢觸媒取代水泥的漿體（水膠比0.3），讓其水化1~28天後，取樣以DSC測定並且確認DSC圖上對應於水泥水化產物如氫氧化鈣、C-S-H膠體、和鈣釩石(AFt)的吸熱峰。結果顯示含廢觸媒的水泥漿體比不含者產生較多的C-S-H膠體但卻較少氫氧化鈣，足以證明這種廢觸媒確實有波索蘭活性，可與氫氧化鈣進行波索蘭反應而加速水泥水化作用；當漿體含有的廢觸媒越多，或者水化時間越長，則產生的C-S-H膠體便越多，而氫氧化鈣便越少。
第三部分以Epcat部分或全部取代活性粉混凝土(RPC)配比中之矽灰。結果顯示，在3、7、28天齡期Epcat取代量為67%時，抗壓強度分別達到72、100和115 MPa，比控制組增加14~30%，原因是Epcat之波索蘭活性比SF大，而加速反應所致。

關鍵字

石油廢觸媒 ； 波索蘭反應 ； 水泥漿 ； 砂漿 ； 抗壓強度 ； 熱示差掃瞄儀 ； 活性粉混凝土

並列摘要

Epcat, a waste catalyst from oil crackers, composed mainly alumina and silica, is expected to have pozzolanic activity.
In this study, pastes and mortars with Epcat were prepared and cured, and their compressive strengths after 3, 7 and 28 curing days were measured. The water/binder (W/B) ratios were 0.2, 0.25 and 0.3, and the replacement levels of cement by Epcat were 0, 5, 10 and 15 wt %. Proper amount of superplasticizer was added into each mix to ensure similar workability. The results indicate that the presence of Epcat would increase the compressive strength of mortars substantially, but increase the compressive strength of the related pastes only slightly. Compared to the the control motor cure at 3-28 days, mixes with 5-15% Epcat increase the compressive strength by amounts ranging from 13 to 41 %. In contrast, pastes with 5-15% Epcat only increase 1.4 to 14.3% in strengths over the plain paste at 3-28 days.
As the W/B ratio decreases or the catalyst content increases, the strength enhancement effect becomes more significant. The improvement in the mechanical properties of mortars is not only due to the increase in the hydrated cement paste itself, but also due to improved bonds between the cement paste and aggregate.
On the other hand, the pozzolanic property of Epcat was studied by using differential scanning calorimeter (DSC). Experimentally, cement pastes (water/binder ratio=0.3) incorporated with 0 ~ 30 wt% Epcat were prepared and cured for 1 ~ 28 days before DSC measurements. The cement hydrated products such as calcium hydroxide, C-S-H gel, and ettringite, were identified from the DSC diagrams of cement pastes. The results show that cement pastes with Epcat present produce more C-S-H and less CH than those without, indicating that the catalyst does accelerate the cement hydration by initiating the pozzolanic reaction with CH. Besides, the effect becomes more prominent when more Epcat was added in cement pastes or the curing time is longer.
Finally, we replace part of silica fume by Epcat in the composition of reactive powder concrete (RPC). When the replacement of silica fume is up to 67%, the compressive strength of the resulting RPC cured at 3, 7 and 28 days are 72, 100 and 115 MPa, respectively. These strength values are 14~30% higher than that of the control. The increase on the compressive strength is due to higher pozzolanic reactivity of Epcat relative to silica fume.

並列關鍵字

Epcat ； pozzolanic reaction ； cement paste ； mortar ； compressive strength ； DSC ； reactive powder concrete