室外花崗巖泛堿原因和處理辦法

1、.天然石材以其自然莊重、色彩絢麗及較好的抗風化穩(wěn)定性、耐磨性、耐酸堿性等特點，被建筑師逐漸認識并廣泛采用于建筑物的室內、外墻面裝飾，極大地突出了建筑的藝術效果。天然石材的安裝施工有干掛法和濕貼法，其中濕貼法具有施工簡便，造價較底的優(yōu)點，但也比較容易產生一些質量通病，突出的一點即是石材表面泛堿現(xiàn)象，產生泛堿后的墻面“水印”斑斑，去之無效，拆之亦難，極大地破壞了建筑裝飾效果。廣州近年建成的一些標志性公共建筑、廣場建筑濕貼花崗巖有泛堿和析白流掛（白胡子）現(xiàn)象，有些甚至十分嚴重，給這一建筑造成無可挽回的損失和遺憾。為此，分析泛堿成因和作相應的預防措施具有重要意義。一、 泛堿現(xiàn)象 (Alkalizati

2、on, Efflorescence)濕貼天然石墻面在安裝期間，石材板塊會出現(xiàn)似“水印”一樣的斑塊，隨著鑲貼砂漿的硬化和干燥，“水印”會稍微縮小，甚至有些消失，其孤立、分散地出現(xiàn)在板塊中，室內程度不嚴重，影響外觀不大。但是，隨著時間推移，特別是外墻反復遭遇雨水或潮濕天氣，水從板縫、墻根等部位侵入，天然石的水斑逐漸變大，并在板縫連成片，板塊局部加深、光澤暗淡、板縫并發(fā)析出白色的結晶體，長年不褪，嚴重影響外觀，此種現(xiàn)象稱為泛堿現(xiàn)象。 二、原因分析Analysis1天然石材結晶相對較粗，存在許多肉眼看不到的毛細管，花崗巖細孔率為0.51.5%，大理石細孔率為0.52.0%，其抗?jié)B性能不如普通水泥砂漿，

3、花崗巖的吸水率0.21.7%是較低的，水仍可由通過石材中的毛細管浸入面?zhèn)鞯搅硗庖幻?。天然石材的這種特性及毛細孔的存在，為粘接材料中的水、堿、鹽等物質的滲入和析出并形成泛堿提供了通道。1. Natural Stone crystal is relatively thick, there are many naked eye can not see the capillary, granite pore rate of 0.5 1.5%, marble pore rate of 0.5 2.0%, its impermeability is lower than ordinary cement m

4、ortar, granite water absorption is as low as 0.2 1.7%, water can still be through the stone from the surface of the capillary immersion reached the other side. This natural stone features and the presence of the pores for the bonding material in the water, alkali, salt, and the infiltration of subst

5、ances such as precipitation provides the channel for the forming of the Alkalization. 2粘結材料產生含堿、鹽等成分物質。主要為鑲貼砂漿析出Ca（OH）2（氫氧化鈣）并跟隨多余的拌合水，沿石材的毛細孔游離入侵板塊，拌合水越多，移動到砂漿表面的Ca（OH）2就越多，水分蒸發(fā)后，Ca（OH）2就存積在板塊里。其他，如在水泥中添加了含有鈉Na+的外加劑，粘土磚土壤含有的Na+、Mg2+、K+、Ca2+、C1-、So42-、C032-等，遇水溶解，會滲透到石材毛細孔里，形成“白華”等現(xiàn)象。 粘結材料產生的含堿、鹽等成分

6、物質是滲入石材毛細孔產生泛堿的直接物質來源。2. Bonded materials produced alkali, salt and other ingredients material. Precipitation is mainly Xiangtie mortar Ca (OH) 2 (calcium hydroxide) and follow the excess mixing water intrusion along the stones pores free plate, mixing more water, move to the mortar surface of Ca (O

7、H) 2 more and more moisture evaporated, Ca (OH) 2 on the deposit accumulated on the plate inside. Others, such as adding cement admixtures containing sodium Na +, clay soil contains Na +, Mg2 +, K +, Ca2 +, C1-, So42-, C032-, etc., dissolved with water, will penetrate into the stone inside the pores

8、 to form a whitish surface and so on. Bonding materials are the source material for alkali, salt and other ingredients to form alkalization.3水的滲入。由于外墻接縫用水泥細砂砂漿勾縫，令防水效果差；地面水（或潮濕）沿墻體或砂漿層侵入石材板；安裝時對石材灑水過多等原因，使水入侵石材板，并溶入Ca（OH）2和其他鹽類物質進入石材毛細管形成泛堿?？梢?，水是泛堿物質的溶劑和載體。 3. Water infiltration. As the outer wall j

9、oint is made with cement sand mortar resulting poor water proof; surface water (or wet) layer of mortar along the wall, or invasive stone plate; installing the stone watering too much and other reasons, so that the water intrusion stone panels, and integration into the Ca (OH) 2 and other salts into

10、 the stone by capillary formation of pan-alkali. This proves that water is the alkalization solvent and carrier.泛堿發(fā)生原理。Theory二、 預防措施 Precaution measures針對泛堿現(xiàn)象的成因，可以相應從切斷泛堿的途徑，減少Ca（OH）2、鹽類等生成物及減少水的侵入三方面采取措施，進行預防。 （一）施工前準備 1設計上考慮消除泛堿，盡可能設計成干掛形式；考慮好結構的防水處理；選擇吸水率及其他物理性能符合要求的石材板等。 2施工前要充分考慮可能發(fā)生泛堿的各施工工藝環(huán)節(jié)

11、，提前作好預防措施，如無把握應先做樣板。 3有關材料應先檢驗后使用，不但要求外觀、尺寸合格，而且其物理性能指標也要合格。 A) pre-construction preparation 1. Use “design” to eliminate the alkalization, as far as possible designed to dry hanging form; considered good water proofing treatment, choose water absorption and other stone panels with physical properti

12、es that meet the requirements 2. Prepare mock-up panel. 3. The material should be tested before using and the appearance, size, qualified, and their physical performance should also be qualified.（二）使用防堿背涂劑 1石板安裝前在石材背面和側面背涂專用處理劑，該溶劑將滲入石材堵塞毛細管，使水、Ca（OH）2、鹽等其他物質無法侵入，切斷了泛堿現(xiàn)象的途徑。無背涂處理，泛堿不可避免，經背涂處理的石材的粘接性

13、不受影響。 2在石材板底涂刷樹脂膠，再貼化纖絲網格布，形成抗拉防水層，但切不可忘記在側面作涂刷處理。 (B) the use of anti-alkali- coating Paint 1. Slate stone before installation in the back and side back Tu-specific treatment agent, the solvent would penetrate stone plug the capillary, so that the water, Ca (OH) 2, salt and other substances can not

14、 be penetrated, cut off the way the phenomenon of alkalization. If there is no base coating processing, alkalization is inevitable, the adhesion is not affected by applying the base coating. 2. Apply resin glue on the base of the stone panel, and paste with fiber mesh to form water proof layer. Do n

15、ot forget to apply the side with the same treatment.（三）減少Ca（OH）2、鹽等物質生成 1鑲貼用的水泥砂漿宜摻入減少劑，以減少Ca(OH)2析出，粘貼法砂漿稠度宜為68cm，灌漿法砂漿稠度宜為812cm。 2室外鑲貼可采用水泥基商品膠粘劑（干混料），它具有良好的保水性，能大大減輕水泥凝結泌水。室內鑲貼可采用石材化學膠粘劑點粘。 (C) reduction of Ca (OH) 2, salt and other substances generated 1. Xiangtie used for mixing cement mortar s

16、hould reduce the dose to reduce the Ca (OH) 2 precipitation and paste France mortar consistency might be desirable for 6 8cm, grouting mortar consistency might be desirable for 8 12cm. 2. Cement-based products can be used outdoors Xiangtie adhesive (dry mixture), which has good water retention, can

17、greatly reduce condensation Bleeding of cement. Stone can be used indoors Xiangtie chemical adhesive sticky point.（四）防止水的侵入 1作業(yè)前不可大量對石材和墻面淋水。 2地面墻根下應設置防潮層、衛(wèi)生間、浴室等用水房間的外壁如有石材裝飾，其內壁應需作防滲處理。 3外墻石材裝飾面，為防止從板縫侵入，墻面板塊必須離縫鑲貼，縫寬不應小于5mm，使用石材專用硅硐耐候密封膠密封。 4室外施工搭設防雨蓬，處理好門窗框周邊與外墻的接縫，防止雨水滲漏入墻。 5鑲貼完成后，室外石材全面積噴涂有機硅防

18、水劑或其他無色護面涂劑。 (D) to prevent water intrusion 1. Do not spray too much water on the stone and the wall. 2. Damp proof membrane should be installed on the wall in the washroom. The wall should be treated with water proofing materials3. For outdoor stone walls, in order to prevent water intrusion from the joint, the wall plate to be away from the seam Xiangtie, Joint should not be less than 5mm, the use of sto