快速预测砂浆强度方法研究

发布时间：2018-12-19 14:21

【摘要】：现阶段，我国建筑施工中用到的砂浆主要是现拌砂浆，其质量受施工条件和外界环境影响很大，若施工中不能有效地控制好砂浆的质量，将会给施工方造成较大的经济损失。施工过程中如果能快速预判砂浆的质量，从而对砂浆的质量进行及时调控，对减少施工方的质量风险将有重大的意义。本文针对砂浆质量控制问题，以建筑中常用的水泥砂浆和混合砂浆（水泥石灰砂浆）为对象，研究了快速预测砂浆强度的方法，主要研究内容和结论如下：（1）借鉴混凝土强度快速预测方法，设计了适合砂浆强度快速预测的试验方法——带模促凝蒸养法，即在量产砂浆样品中加入促凝剂CS，搅拌均匀后，制成砂浆试件（40mm×40mm×50mm）并带模进行高温蒸汽养护，根据加速养护的早期强度预测标准养护28d强度，并给出了“砂浆加速蒸养法企业标准”。（2）分别对常用强度等级（M5、M7.5、M10）的水泥砂浆和混合砂浆进行了配合比设计、试件设计、加速养护试验和标准养护试验，获得了60组1080个试件的强度测试数据。（3）研究了加速养护砂浆早期强度与标准养护28d砂浆强度的相关关系，分别建立了一元、二元、三元线性数学模型，并运用MATLAB软件进行数值回归，分析得到相应的强度预测公式。一元线性回归模型只需用3.5h（或4.5h）加速养护砂浆强度一个变量，能够方便快速地预测常用砂浆强度；二元线性模型需用3.5h和4.5h加速养护砂浆强度两个变量，能够得到更加精确的预测结果；三元线性模型需要用到砂浆配合比（砂与水泥的质量比）S/C及3.5h、4.5h加速养护砂浆强度三个变量，可以用于不同强度等级，不同类型的砂浆强度的预测，，适用范围更加广泛。（4）研究了人工神经网络在预测砂浆强度中的应用，运用MATLAB软件建立了预测水泥砂浆和混合砂浆强度的BP神经网络模型，并对模型精度进行了测试，与传统回归模型相比，其试验结果稳定可靠。（5）获得了水泥砂浆和混合砂浆（水泥石灰砂浆）在蒸养养护条件下的强度发展规律。在加速养护条件下，砂浆试块的强度值和强度比（加速养护强度与标准养护28d强度之比）随着养护时间的增加总体上呈增大的趋势；随着水泥用量的增大，参与凝结硬化反应水泥的绝对量值增加，相对量值也增加，但增幅较小；在养护时间较大时（3.5h和4.5h），强度测试值往往表现出较好的相关性和较小的离散性，因此采用较大养护时间的强度测试值对28d标养强度进行预测，可以提高预测精度。
[Abstract]:At present, the mortar used in the construction of our country is mainly mixed mortar, the quality of which is greatly affected by the construction conditions and the external environment. If the quality of the mortar can not be effectively controlled in construction, it will cause great economic losses to the construction side. It will be of great significance to reduce the quality risk of construction if the quality of mortar can be predicted quickly and the quality of mortar can be adjusted in time. In this paper, aiming at the quality control of mortar, taking cement mortar and mixed mortar (cement lime mortar), which are commonly used in building, as the object, the method of rapid prediction of mortar strength is studied. The main research contents and conclusions are as follows: (1) based on the rapid prediction method of concrete strength, a suitable test method for rapid prediction of mortar strength is designed, I. e., adding coagulant CS, to the mass produced mortar sample. After mixing evenly, the mortar specimen (40mm 脳 40mm 脳 50mm) was made into high temperature steam curing with mould. According to the early strength of accelerated curing, the curing strength of 28 days was predicted, and the enterprise standard of accelerated steam curing of mortar was given. (2) the mixture ratio design of cement mortar and mixed mortar of common strength grade (M5 / M7.5M10) was carried out, the specimen design, accelerated curing test and standard maintenance test were carried out, and the strength test data of 60 groups of 1080 specimens were obtained. (3) the relationship between the early strength of accelerated curing mortar and the strength of standard curing mortar for 28 days is studied. The linear mathematical models of monolithic, binary and ternary are established, and the numerical regression is carried out by using MATLAB software. The corresponding strength prediction formula is obtained by analysis. The univariate linear regression model only needs 3.5h (or 4.5h) to accelerate the curing strength of mortar, which can be used to predict the strength of commonly used mortar conveniently and quickly. The binary linear model needs two variables of 3.5 h and 4.5 h to accelerate curing mortar strength, which can get more accurate prediction results. In the ternary linear model, three variables, S / C (mass ratio of sand to cement) and 3.5 h / 4.5h accelerated curing mortar strength, can be used to predict the strength of mortar of different strength grades and types. The scope of application is wider. (4) the application of artificial neural network in predicting mortar strength is studied. The BP neural network model for predicting the strength of cement mortar and mixed mortar is established by using MATLAB software. The precision of the model is tested and compared with the traditional regression model. The test results are stable and reliable. (5) the strength development law of cement mortar and mixed mortar (cement lime mortar) under steam curing condition was obtained. Under the condition of accelerated curing, the strength value and strength ratio (the ratio of accelerated curing strength to standard curing strength of 28 days) showed an increasing trend with the increase of curing time. With the increase of cement content, the absolute value of cement involved in the condensation hardening reaction increased, and the relative value also increased, but the increase was relatively small. When the curing time is longer (3.5h and 4.5h), the strength test value often shows better correlation and less dispersion. Therefore, the 28d standard strength is predicted by the strength test value of the larger curing time. The prediction accuracy can be improved.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU578.1

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