8 S Density and Porosity Log Data and analysis Enter the initial specimen dimensions to the nearest 0.1 mm in the following table: Depth, d (mm) Height, h (mm) 95
Specimen concretel 61 concrete 2 62 clay AAC Width, w (mm) Concrete clay AAC 63 69 Specimen Concrete 2520.0 2605.3 1-Volume: V= Record the mass of each specimen to the 2nd decimal point. msat 2.7736 2.824 1.5218 1893 1437.1 92 4.7 msat-mArc Pw. Dry mass, mary (9) Saturated mass, msat (9) 277366 V 2 Bulk density Phulk mdry * 3-Matrix density Pmat=Vmatrix Hygro Lab = m Dry 98 misat mory V R 98 2.57 2.6063 1.4371 Calculate the bulk density, matrix density and open porosity values using the formulae provided can use Pw = 1000 below. Check units carefully. Formula provided below. Note: pw=997 ko Formula 215 213 282440 152168 127.70 792099 6 0 214 1342208,0 1189.3 Archimedes mass, marc (g) 4- Volume of pores V₁ 0.9297 6- Open porosity Po Volume (mm³) msat-Mdry Pw 5- Total Volume Vtotal = Vpores +Vmatrix 12 45 925,0 1294188.0 153 4,8 1 1537.5 849.7 pores - Using the formulae above, calculate the bulk density, matrix density and open porosity in the table below, Vpores V mAre 1.5375 0.8447 1, 5348 Specimen Concreate Concrecte clay A AC 1 V/₁ HAY - Bulk density, Poutk (kg/m³) 20675 2019.6 2116.2 4 V pore 1 1.243x10-3 2,042×10 .3 2 1.290 X10¹² 2,193 x 10-6 Hygro Lab 68 Matrix density, Pmat (kg/m³) 2474.0 2433, 3 2418.7 Vmatriy Open Porosity 1.0788X103 07799 5.9415×10 3 6.791 × 10 + 8,495 × 10 -15 0F903 1.0707 x 10² 4 2,653 x 10°4 2164 0.125 Hygro Lab Assessment questions 1. How does the volume experimentally determined compare to that by measurement? Why might they be different? tо compare The day VT 61791x104m²³ V 7,920 x 10°x m²³ it's diffrent frow what we expected initally in our first caculation at may be because of the unperfect shape aj"/ /1 2. Compare the open Porosity of the samples. What do your results tell you? The 1 concrete has 6,164). open porosity while the 2 concreate has oil? this mean that 2 Concreat has Size which mean it's have a higher open porosity 69 larger particles Experiment 2 -Sorptivity Guidelines Sorptivity testing measures the water uptake through capillary rise within a pore structure over open porosity. Sorptivity testing can be used to measure to characterise the resistance to ingres The sorptivity rate can be affected by mineralogical composition of the sample but predominantly shows that porosity is due to capillary forces which are greatest on dry specimens and be two stage primary and secondary, for this lab you will only consider primary. Unsaturated flow the additionally, it can be used to determine the healing potential of concrete. Sorptivity testing falls negligible on saturated. Materials of time. The samples (Clay brick section, Autoclaved aerated concrete (AAC) section, two conc block section) provided have been oven dried at 60°C for 5 days and allowed to cool to ambie This experiment determines the sorptivity rate which is the height of absorption over the square temperature prior to your lab (Figure 2). ● Clay brick Figure 2- Testing materials for sorptivity ● Hygro Lab Two concrete block section Equipment required This experiment requires: Testing materials (clay brick section, aerated block section, two concrete block section) Scales Measurement device (ruler or callipers) Plastic water tray Sample supports (washers) Water Stopwatch Cloth Autoclaved aerated concrete (AAC) Equipment and Procedure 1. For each sample record its name as well as width (w), depth (d) and height (h). 2. Place the plastic water tray on a flat, level surface. 3. Place a washer under each corner of every sample inside the plastic water tray, ensure correct spacings, 4. Pour water into the container to 5.0+ 1.0 mm above the washers. 5. Record the dry mass of each specimen. 70 e over time. minantly the e to ingress ng falls into flow theary nd become square root o concrete to ambient ed 1 =tion) re correct For the next stage you need to consider the timings carefully before you start. Please read the procedure in full before starting the next phase. In particular do a dry run of how long is required to complete the steps for one sample before you start. Student 1: Place a sample onto the washers with the smaller cross section as the base. Student 2: Start the stopwatch. Student 1: At the designated time interval (question 2 of the sorptivity worksheet) provided in your worksheet remove the specimen, pat dry and place on scales. Student 2. Record the ● ● ● Hygro Lab ● mass. Student 1: Place the specimen back onto the washers. Student 2: Ensure the scales are dry and zeroed. This process is repeated for all specimens at the predetermined time intervals as shown in Table of your worksheet. Answer the questions in your worksheet 71
