Cracks in cement-based mortar, putty and cracks are common problems. In many years of research and practice, the author believes that the cracks of plastering mortar, putty on exterior wall and the causes of cracks mainly come from "internal" and "external" aspects.

　　1撇寞、“內(nèi)因”方面

　　1. Internal Causes

　　“內(nèi)因”方面主要是由于一些抹面砂漿、膩子產(chǎn)品的干縮性大堂氯、干縮快蔑担，產(chǎn)生較大內(nèi)應(yīng)力破壞了砂漿結(jié)構(gòu)而引起裂紋的，裂紋的表現(xiàn)一般呈不規(guī)則的龜裂狀咽白，也就是常說的龜裂紋啤握，主要是一些生產(chǎn)廠家對原材料性質(zhì)、作用與技術(shù)原理上了解不充分晶框，所用原材料不符合要求排抬，配方不科學(xué)，導(dǎo)致產(chǎn)品質(zhì)量不穩(wěn)定授段、抗裂性能差畜埋，施工后不久就出現(xiàn)大面積龜裂莫绣、空鼓、脫落問題镀材。

　　"Internal cause" is mainly due to the drying shrinkage of some plastered mortar and putty products, which causes cracks due to the destruction of mortar structure by large internal stress. The cracks generally show irregular tortoise cracks, that is to say, tortoise cracks. The main reason is that some manufacturers do not fully understand the nature, function and technical principles of raw materials, and the raw materials used do not conform to each other. According to the requirements, unscientific formulation leads to unstable product quality and poor crack resistance. Large area cracking, empty drum and shedding problems occur shortly after construction.

　　水泥砂漿的強(qiáng)度妆浅、防裂效果都與水有重要關(guān)系，水泥的水化與凝結(jié)硬化是一個漸進(jìn)式忍具、連續(xù)性過程爵缸，先水化，后凝結(jié)却怪，凝結(jié)硬化結(jié)果如何晚饰，要取決于水化條件，水化的越充分殷感、水養(yǎng)護(hù)的越好窃橄、水養(yǎng)護(hù)的時間越長，強(qiáng)度就會越高熏迷，收縮性就越小赵腰，防裂效果就越好；水泥的水化與凝結(jié)硬化速度受環(huán)境溫度的影響也是明顯的谐歪，即環(huán)境溫度高敦间，水化與硬化速度就快，環(huán)境溫度低時束铭，水泥的水化與凝結(jié)硬化的速度相應(yīng)就慢些廓块。凡是早干、早硬契沫、早強(qiáng)的水泥砂漿带猴，因保水不好、自養(yǎng)護(hù)能力差懈万，會產(chǎn)生收縮過快浓利、收縮力過強(qiáng)、容易產(chǎn)生大面積龜裂钞速。在研究與實踐中，早干嫡秕、早硬渴语、早強(qiáng)的水泥砂漿的后期強(qiáng)度及穩(wěn)定性、抗裂性均比晚干昆咽、晚硬驾凶、晚強(qiáng)的水泥砂漿要差，這也是水泥作為無機(jī)水硬性膠凝材料的特殊性所決定的鉴梦。

　　The strength and anti-cracking effect of cement mortar are closely related to water. The hydration and condensation hardening of cement are a gradual and continuous process. The results of hydration first, then, and condensation hardening depend on the hydration conditions. The more fully hydration, the better water curing and the longer water curing time, the higher the strength, the smaller the shrinkage and the better the anti-cracking effect. The rate of cement hydration and setting hardening is also obviously affected by environmental temperature, that is, the rate of hydration and hardening is faster when the environmental temperature is high, and the rate of cement hydration and setting hardening is slower when the environmental temperature is low. The cement mortar with early drying, early hardening and early strength will shrink too fast, shrink too strongly and easily crack in large area due to poor water retention and poor self-curing ability. In research and practice, the late strength, stability and crack resistance of early-drying, early-hardening and early-strength cement mortar are worse than those of late-drying, late-hardening and late-strength cement mortar, which is also determined by the particularity of cement as inorganic hydraulically cementing material.

　　龜裂紋的產(chǎn)生氛灸，主要與水泥有關(guān)耘泰，不論是什么類型的水泥，都存在干縮問題剑碌，從試驗情況看嘀醋，硫鋁酸鹽水泥、白水泥等水泥品種的后期強(qiáng)度及穩(wěn)定性孟溯、抗裂性就不及普通硅酸鹽水泥好讲侵，主要是這些產(chǎn)品本身的收縮性大，干縮較快呜款、收縮力較強(qiáng)耸壮、容易產(chǎn)生龜裂紋。普通硅酸鹽水泥在我國建筑工程上的應(yīng)用很普遍剩症，有好幾十年的歷史笑驶，它的性能是很好的，經(jīng)研究與試驗胞饭，只要水化充分嫌变、水養(yǎng)護(hù)條件較好，幾年后袋马、甚至十年后其強(qiáng)度還會有所提高初澎。目前，聚合物砂漿虑凛、水泥類膩子仍以普通硅酸鹽水泥為主碑宴，所使用的型號為32.5R或42.5R，其在聚合物抹面砂漿桑谍、水泥類膩子產(chǎn)品中的配方量一定要掌握好延柠。

　　The crack of tortoise is mainly related to cement. No matter what type of cement, there is drying shrinkage problem. From the test results, the strength, stability and crack resistance of sulphoaluminate cement, white cement and other cement varieties are not as good as ordinary Portland cement. The main reason is that these products have larger shrinkage, faster drying shrinkage, stronger shrinkage force and are prone to tortoise crack. Ordinary Portland Cement is widely used in China's construction engineering. It has a history of several decades. Its performance is very good. Through research and test, as long as the hydration is sufficient and the water maintenance condition is good, its strength will be improved in a few years or even ten years. At present, polymer mortar and cement putty are still based on ordinary Portland cement. The type used is 32.5R or 42.5R. The formulation of polymer plastering mortar and cement putty products must be well controlled.

　　2、“外因”方面

　　“外因”方面锣披，主要是施工工藝贞间、地基和自然環(huán)境引起的。通常情況下雹仿，建筑設(shè)計施工不科學(xué)和不合理增热，地基沉降、偏離胧辽，施工時一次性抹的太厚嗤矾、施工前基底已經(jīng)出現(xiàn)明顯裂縫、地震悄锈、大的風(fēng)壓產(chǎn)生的應(yīng)力拒牡、施工后連續(xù)性的高溫干旱天氣等，都會引起裂縫的產(chǎn)生菌渐，裂縫随去、裂紋的表現(xiàn)一般以裂縫為多亮钩，形狀有橫線式、豎線式或呈不規(guī)則式扔泵。

　　The external causes are mainly caused by construction technology, foundation and natural environment. Usually, unscientific and unreasonable architectural design and construction, settlement and deviation of foundation, excessive thickness of one-time plastering during construction, obvious cracks in basement before construction, earthquake, stress caused by large wind pressure, continuous high temperature and drought weather after construction, etc., will cause cracks. Cracks and cracks are generally manifested in the form of horizontal lines and vertical lines. Type or irregular.

　　3巢驶、水泥砂漿與水泥基膩子的裂紋裂縫的另一個特征是：無論抹多厚或抹多薄，其裂紋裂縫都是從面一直裂到底荡担，這也是建筑物發(fā)生滲漏水的根本原因品客。裂紋裂縫有大小之分，大的裂紋裂縫可以很容易看到准瘪，小的裂紋裂縫肉眼不一定看得出來粟翔，但只要往干燥的墻面上潑灑水，微細(xì)的裂紋裂縫就能清楚地看到讼载。

　　3. Another characteristic of crack in cement mortar and cement-based putty is that no matter how thick or thin it is, the crack always cracks from the surface to the end, which is also the most fundamental reason for water leakage in buildings. Cracks can be divided into different sizes. Large cracks can be easily seen. Small cracks may not be visible to the naked eye, but as long as water is sprinkled on the drying wall, fine cracks can be clearly seen.

　　4轿秧、只要出現(xiàn)裂紋、裂縫咨堤，基本上沒有什么可靠的材料和技術(shù)手段可以徹底修復(fù)菇篡，其結(jié)果會給建筑裝飾、裝修一喘、防水工程以及今后的維修工作造成極大的困難驱还，這是因為外墻裂縫、裂紋在隨著外部所處的環(huán)境條件(地基沉降凸克、地震等)和較大溫差议蟆、干濕度變化的同時，其縫隙大小萎战、形狀也在隨之不停地變化咐容，即冬季低溫與夏季高溫時縫隙大小會變化，就是在同一季節(jié)下雨天與晴朗天蚂维，縫隙大小也會發(fā)生變化戳粒，總之每天24小時都處于變化之中，這也是裂縫侦广、裂紋在屋面恼芙、墻面、地下防水工程及維修實踐中成猴，也是令人頭痛的事龟冻，經(jīng)常是修好后，不到一年甚至是幾個月內(nèi)软殿，又開始滲漏。只要沒有任何裂紋裂縫巴锄，一般情況下建筑物是不會發(fā)生滲漏水的骨惫，凡了解水泥水池的人钱挺，就明白只要沒有任何裂紋裂縫，水泥水池是不會發(fā)生滲漏水的蜀勃。

　　4. As long as cracks and cracks occur, there is basically no reliable material and technical means to repair them thoroughly. The result will cause great difficulties in building decoration, decoration, waterproof engineering and future maintenance. This is because cracks and cracks in external walls are accompanied by environmental conditions (foundation settlement, earthquakes, etc.) and at the same time with large temperature difference and dry humidity change. The size and shape of cracks are constantly changing, that is, the size of cracks will change when the temperature is low in winter and high in summer. Even in rainy and sunny days in the same season, the size of cracks will change 24 hours a day. This is also the most headache of cracks and cracks in roof, wall, underground waterproof Engineering and maintenance practice. Often it starts to leak again in less than a year or even a few months after repair. As long as there are no cracks, the building will not leak water in general. Anyone who knows the cement pool knows that as long as there are no cracks, the cement pool will not leak water.