Cau 3:

Loai da

80

40

20

10

5

1

120

1080

1590

180

30

2

0

60

1160

1710

60

San h=8cm; h0=6cm

Bai giai:

Loai1: Cap phoi lien tuc tieu chuan cua da dam:

Sang

80

40

20

10

5

M

123

1080

1590

180

30

ai %

4

36%

53

6

1

Ai %

4

40

93

99

100

Dmax= 80mm; ADmax= 4%

Dmin= 10mm; ADmin= 99%

1/2 (Dmax+ Dmin) =40 →A1/2= 36%

→Thoa man cap phoi tieu chuan:

Ta co Dmax= 80mm >3/4 h0 = 3/4.60= 45mm

Loai 2:

sang

80

40

20

10

5

m

0

60

1160

1710

60

ai %

0

2

38/67

57

2

Ai%

0

2

40/67

97,67

99,67

Dmax= 40mm; ADmax= 2%

Dmin= 5mm; ADmin= 99,67%

→ thoa man cap phoi tieu chuan

Dmax= 40mm <3/4 h0= 45mm

Dmax= 40mm ≤1/2h0= 40mm

→thoa man

Vay co the do BT bang cot lieu da dam nay

Cau 1: Cuong do va cac phuong phap xac dinh Mac cua XM poolang?

1/ Cuong do:

* D/n: la dai luong dac trung cho XM o trang thai pha hoai duoi t/d cua luc

* T/c:

- Cuong do cua XM phat trien ko deu: trong 3 ngay co the dat 40-50% mac XM, 7 ngay dau 60-70%. Trong nhung ngay sau toc do tang cuong do con cham hon, den 28 ngay dat duoc mac

- Cuong do cua XM co the ↑ hang thang, tham chi hang nam, vuot 2-3 lan cuong do 28 ngay. Co the coi toc do ↑ cuong do trung binh cua XM tren theo ham luong logarit.

- Cuong do cua da XM va toc do cung ran phu thuoc vao t/phan khoang vat cua Clanke, do min cua XM, do am va t° cua mtruong, tgian bao quan XM.

- Toc do ↑ cuong do cua cac khoang rat khac nhau: C3S co do tang cuong do nhanh nhat, C2S co toc do ↑ cuong do cham.

2/ Cac phuong phao x/d mac cua XM:

Mac cua XM duoc xd theo cuong do chiu uon cua 3 mau vua XM (kich thuoc 4x4x16cm) che tao tu hon hop XM-cat bang 1:3 va luong nuoc yeu cau, duong ho 28 ngay trong dieu kien tieu chuan (1 ngay trong khuon o ngoai khong khi am, 27 ngay sau trong nuoc o t° thuong) va theo cuong do chiu nen cua 6 nua mau.

Cau 2: Phan tich a/h cua cac truc va cau tao den k/nang chiu luc cua VLXD. Tu do rut ra nguyen ly chung che tao VL co cuong do cao:

1/ A/huong cua cau truc va cau tao:

* Cau truc vi mo

- Hat toan khoi: da nhan tao dac nhu BT nang, BT nhe cau tao dac, VL go^’m… → cuong do cao, kha nang chong tham, tinh chong an mon tot nhung no nang ne, cac tinh chat ve am va nhiet kem

- VL co cau tao rong (BT khi, BT bot…

→ cuong do, do chong an mon, chong tham kem hon VL dac cung loai nhung kha nang cach nhiet, cach am lai tot.

- VL co cau tao dang soi nhu go, bong khoang, bong thuy tinh → cuong do, do dan nhiet va cac tinh chat rat khac nhau theo phuong doc va phuong ngang tho’.

- VL gom cac hat roi rac → co t/c tuy thuoc vao thanh phan, do lon vat rang thai be mat