搗實方式對透水混凝土之強度及透水性影響

Effects of Tamping Methods on the Strength and the Water Permeability of Pervious Concrete

潘崧傑(Song-Jay Pan)

指導教授 ： 盧俊愷 ； 吳志興

國立屏東科技大學/工學院/土木工程系所/碩士(2016年)

摘要

本文以水泥用量C=266 kg、水灰比W/C=0.54之透水混凝土配比，用不同搗實方式製作試體，骨材粒徑為4.75~12.5 mm。施作垂流量、單位重和含氣量、抗壓強度、抗彎強度、透水係數及孔隙率試驗，其試驗值再與現地滾壓之透水混凝土試驗值作比較，以尋求與現地滾壓最相符的搗實方式。試體有鑄模搗實試體和現地鋪面之鑽心試體，現地壓實方式是以輪寬1.35 m之2噸壓路機來回滾壓4至5次。搗實工具為鋼棒和夯錘，夯錘又分大、小鋼製夯錘。依抗壓強度試體用圓形鋼棒分4層搗實，每層搗實14次，定義為1倍搗實，以計算其他試體之搗實次數。試驗以2倍及3倍搗實程度製作試體。
試驗結果顯示，以鋼棒和夯錘3倍搗實試體之28天抗壓強度與現地滾壓之值相當，前者為125和116 kgf/cm2，後者為122 kgf/cm2。鋼棒和夯錘3倍搗實之fc7/fc28值各為0.92和0.97，現地鑽心試體之fc7/fc28值為0.63。顯示鑄模試體之透水混凝土有早強作用，而現地僅早、晚灑水養護，7天之水泥水化作用尚未完全，但28天後水化則較完全。
抗彎強度試驗3倍搗實試體之28天破裂模數R28=27.09 kgf/cm2，7天和28天之破裂模數比R7/R28=0.86。鑄模試體3倍搗實與現地鑽心試體之透水係數k皆大於基準值0.01 cm/sec，孔隙率n值皆大於基準值15%，透水係數k和孔隙率n值皆隨齡期增加而降低。
在新拌混凝土單位重和含氣量試驗方面，3倍搗實試樣之單位重U=2019 kg/m3、含氣量Air=17.3%。依此修正透水混凝土試拌配比為水泥用量C=284 kg、用水量W=154 kg、骨材用量G=1852 kg。

關鍵字

透水混凝土 ； 搗實方式 ； 透水係數 ； 孔隙率 ； 抗壓強度

並列摘要

The thesis used a pervious concrete mix of cement amount C = 266 kg, water-cement ratios W/C = 0.54 to make specimens by different tamping methods. Aggregate particle size was between 4.75~12.5 mm. The specimens were made by different tamping methods, and were performed the flow, compressive strength, flexural strength, permeability coefficient, and porosity tests. The test results were then compared with those from the rolled pavement in situ to seek the most suitable tamping methods agreed with the compaction on pavement. The pervious concrete specimens were tamped in the molds as well as taken from pavement compacted by roller. The pavement in situ was compacted by a 2-ton roller with 1.35 m roll wide and rolled back and forth four or five times. Tamping tools were steel rods and steel rammers. The steel rammers had large rammer and small rammer. The one time degree impaction specimen here was defined as the specimen of the compressive test was impacted in 4 layers, 14 times each layer by the round steel rods. From the definition, the tamped times of other specimens could be calculated. The specimens for the tests were made by double and triple degree of impaction.
The test results showed that, the values of the 28-day compressive strength of triple degree impaction specimen by the steel rod or by the steel rammer were close to that of the rolled pavement. The former were 125 and 116 kgf/cm2, and later was 122 kgf/cm2. The ratio 7 day to 28 day compressive strength fc7/fc28 of triple degree impaction by the steel rod and steel rammer were 0.92 and 0.97. The fc7/fc28 of the core taken the rolled pavement was 0.63. The results showed that, the pervious concrete specimens tamped in the molds had accelerating effect, while the pervious concrete in pavement was cured only in morning and late afternoon, the cement hydration was not complete after 7 days. However, after 28 day, the cement hydration was much more complete.
The 28-day modulus of rupture R28=27.09 kgf/cm2 from the flexural strength test of triple degree impaction specimen by the steel rod. The ratio of modulus of rupture R7/R28=0.86. All the permeability coefficients k were larger than the criteria value 0.01 cm/sec, and all the porosities n were greater than the criteria value 15%. The porosity n and permeability coefficient k values were decreased with age increased.
In the unit weight and air content test for fresh concrete, the unit weight of triple degree impacting U=2019 kg/m3 and air content Air=17.3%. From the test result, the mix of the pervious concrete was modified as cement amount C=284 kg, water amount W=154 kg, and aggregate amount G=1852 kg.

並列關鍵字

pervious concrete ； tamping methods ； permeability coefficient ； porosity ； compressive strength

參考文獻

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